diff --git a/docs/src/whatsnew/latest.rst b/docs/src/whatsnew/latest.rst
index 51adfb9d8d..79223944a2 100644
--- a/docs/src/whatsnew/latest.rst
+++ b/docs/src/whatsnew/latest.rst
@@ -125,6 +125,8 @@ This document explains the changes made to Iris for this release
 
 #. `@HGWright`_ fixed some typo's from Gitwash. (:pull:`5145`)
 
+#. `@Esadek-MO`_ added notes to function docstrings to
+   to clarify if the function preserves laziness or not. (:pull:`5137`)
 
 💼 Internal
 ===========
diff --git a/lib/iris/analysis/__init__.py b/lib/iris/analysis/__init__.py
index 173487cfb0..9444d38199 100644
--- a/lib/iris/analysis/__init__.py
+++ b/lib/iris/analysis/__init__.py
@@ -2032,6 +2032,7 @@ def interp_order(length):
 
     result = cube.collapsed('longitude', iris.analysis.MEDIAN)
 
+
 This aggregator handles masked data, but NOT lazy data.  For lazy aggregation,
 please try :obj:`~.PERCENTILE`.
 
diff --git a/lib/iris/pandas.py b/lib/iris/pandas.py
index 417b6b11de..522c216432 100644
--- a/lib/iris/pandas.py
+++ b/lib/iris/pandas.py
@@ -159,6 +159,8 @@ def as_cube(
             as_cube(series, calendars={0: cf_units.CALENDAR_360_DAY})
             as_cube(data_frame, calendars={1: cf_units.CALENDAR_STANDARD})
 
+    Since this function converts to/from a Pandas object, laziness will not be preserved.
+
     """
     message = (
         "iris.pandas.as_cube has been deprecated, and will be removed in a "
@@ -240,6 +242,8 @@ def as_cubes(
 
     :class:`dask.dataframe.DataFrame`\\ s are not supported.
 
+    Since this function converts to/from a Pandas object, laziness will not be preserved.
+
     Examples
     --------
     >>> from iris.pandas import as_cubes
@@ -599,6 +603,10 @@ def as_series(cube, copy=True):
     If you have a large array that cannot be copied,
     make sure it is not masked and use copy=False.
 
+    Notes
+    ------
+    Since this function converts to/from a Pandas object, laziness will not be preserved.
+
     """
     message = (
         "iris.pandas.as_series has been deprecated, and will be removed in a "
@@ -809,6 +817,10 @@ def as_data_frame(
     419903    298.995148
     Name: surface_temperature, Length: 419904, dtype: float32
 
+    Notes
+    ------
+    Since this function converts to/from a Pandas object, laziness will not be preserved.
+
     """
 
     def merge_metadata(meta_var_list):
diff --git a/lib/iris/plot.py b/lib/iris/plot.py
index f87d74b020..47e345b83c 100644
--- a/lib/iris/plot.py
+++ b/lib/iris/plot.py
@@ -1112,6 +1112,11 @@ def contour(cube, *args, **kwargs):
     See :func:`matplotlib.pyplot.contour` for details of other valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     result = _draw_2d_from_points("contour", None, cube, *args, **kwargs)
     return result
@@ -1136,6 +1141,11 @@ def contourf(cube, *args, **kwargs):
     See :func:`matplotlib.pyplot.contourf` for details of other valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     coords = kwargs.get("coords")
     kwargs.setdefault("antialiased", True)
@@ -1200,6 +1210,11 @@ def default_projection(cube):
         import matplotlib.pyplot as plt
         ax = plt.ax(projection=default_projection(cube))
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     # XXX logic seems flawed, but it is what map_setup did...
     cs = cube.coord_system("CoordSystem")
@@ -1218,6 +1233,11 @@ def default_projection_extent(cube, mode=iris.coords.POINT_MODE):
             points, or the limits of the cell's bounds.
             The default is iris.coords.POINT_MODE.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     extents = cartography._xy_range(cube, mode)
     xlim = extents[0]
@@ -1255,7 +1275,13 @@ def _fill_orography(cube, coords, mode, vert_plot, horiz_plot, style_args):
 
 
 def orography_at_bounds(cube, facecolor="#888888", coords=None, axes=None):
-    """Plots orography defined at cell boundaries from the given Cube."""
+    """Plots orography defined at cell boundaries from the given Cube.
+
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+    """
 
     # XXX Needs contiguous orography corners to work.
     raise NotImplementedError(
@@ -1288,7 +1314,13 @@ def horiz_plot(v_coord, orography, style_args):
 
 
 def orography_at_points(cube, facecolor="#888888", coords=None, axes=None):
-    """Plots orography defined at sample points from the given Cube."""
+    """Plots orography defined at sample points from the given Cube.
+
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+    """
 
     style_args = {"facecolor": facecolor}
 
@@ -1334,6 +1366,11 @@ def outline(cube, coords=None, color="k", linewidth=None, axes=None):
         The axes to use for drawing.  Defaults to the current axes if none
         provided.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     result = _draw_2d_from_bounds(
         "pcolormesh",
@@ -1376,6 +1413,11 @@ def pcolor(cube, *args, **kwargs):
     See :func:`matplotlib.pyplot.pcolor` for details of other valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     kwargs.setdefault("antialiased", True)
     kwargs.setdefault("snap", False)
@@ -1410,6 +1452,11 @@ def pcolormesh(cube, *args, **kwargs):
     See :func:`matplotlib.pyplot.pcolormesh` for details of other
     valid keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     result = _draw_2d_from_bounds("pcolormesh", cube, *args, **kwargs)
     return result
@@ -1435,6 +1482,11 @@ def points(cube, *args, **kwargs):
     See :func:`matplotlib.pyplot.scatter` for details of other valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
 
     def _scatter_args(u, v, data, *args, **kwargs):
@@ -1526,6 +1578,11 @@ def barbs(u_cube, v_cube, *args, **kwargs):
     See :func:`matplotlib.pyplot.barbs` for details of other valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     #
     # TODO: check u + v cubes for compatibility.
@@ -1576,6 +1633,11 @@ def quiver(u_cube, v_cube, *args, **kwargs):
     See :func:`matplotlib.pyplot.quiver` for details of other valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     #
     # TODO: check u + v cubes for compatibility.
@@ -1622,6 +1684,11 @@ def plot(*args, **kwargs):
     See :func:`matplotlib.pyplot.plot` for details of additional valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     if "coords" in kwargs:
         raise TypeError(
@@ -1654,6 +1721,11 @@ def scatter(x, y, *args, **kwargs):
     See :func:`matplotlib.pyplot.scatter` for details of additional
     valid keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     # here we are more specific about argument types than generic 1d plotting
     if not isinstance(x, (iris.cube.Cube, iris.coords.Coord)):
@@ -1689,6 +1761,11 @@ def fill_between(x, y1, y2, *args, **kwargs):
     See :func:`matplotlib.pyplot.fill_between` for details of additional valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     # here we are more specific about argument types than generic 1d plotting
     if not isinstance(x, (iris.cube.Cube, iris.coords.Coord)):
@@ -1721,6 +1798,11 @@ def hist(x, *args, **kwargs):
     See :func:`matplotlib.pyplot.hist` for details of additional valid
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     if isinstance(x, iris.cube.Cube):
         data = x.data
@@ -1767,6 +1849,11 @@ def symbols(x, y, symbols, size, axes=None, units="inches"):
     * units: ['inches', 'points']
         The unit for the symbol size.
 
+    Notes
+    ------
+    This function does maintain laziness when called; it doesn't realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     if axes is None:
         axes = plt.gca()
@@ -1892,6 +1979,11 @@ def animate(cube_iterator, plot_func, fig=None, **kwargs):
     >>> ani = iplt.animate(cube_iter, qplt.contourf)
     >>> iplt.show()
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     kwargs.setdefault("interval", 100)
     coords = kwargs.pop("coords", None)
diff --git a/lib/iris/quickplot.py b/lib/iris/quickplot.py
index c992cfdbf0..9209d4b3b7 100644
--- a/lib/iris/quickplot.py
+++ b/lib/iris/quickplot.py
@@ -174,6 +174,11 @@ def contour(cube, *args, **kwargs):
 
     See :func:`iris.plot.contour` for details of valid keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     coords = kwargs.get("coords")
     axes = kwargs.get("axes")
@@ -201,6 +206,10 @@ def contourf(cube, *args, **kwargs):
 
     See :func:`iris.plot.contourf` for details of valid keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
     coords = kwargs.get("coords")
     axes = kwargs.get("axes")
@@ -229,6 +238,11 @@ def outline(cube, coords=None, color="k", linewidth=None, axes=None):
         The width of the lines showing the cell outlines. If None, the default
         width in patch.linewidth in matplotlibrc is used.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     result = iplt.outline(
         cube, color=color, linewidth=linewidth, coords=coords, axes=axes
@@ -244,6 +258,10 @@ def pcolor(cube, *args, **kwargs):
 
     See :func:`iris.plot.pcolor` for details of valid keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
     coords = kwargs.get("coords")
     axes = kwargs.get("axes")
@@ -258,6 +276,11 @@ def pcolormesh(cube, *args, **kwargs):
 
     See :func:`iris.plot.pcolormesh` for details of valid keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     coords = kwargs.get("coords")
     axes = kwargs.get("axes")
@@ -272,6 +295,11 @@ def points(cube, *args, **kwargs):
 
     See :func:`iris.plot.points` for details of valid keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     coords = kwargs.get("coords")
     axes = kwargs.get("axes")
@@ -288,6 +316,11 @@ def plot(*args, **kwargs):
     See :func:`iris.plot.plot` for details of valid arguments and
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     axes = kwargs.get("axes")
     result = iplt.plot(*args, **kwargs)
@@ -303,6 +336,11 @@ def scatter(x, y, *args, **kwargs):
     See :func:`iris.plot.scatter` for details of valid arguments and
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     axes = kwargs.get("axes")
     result = iplt.scatter(x, y, *args, **kwargs)
@@ -317,6 +355,10 @@ def fill_between(x, y1, y2, *args, **kwargs):
     See :func:`iris.plot.fill_between` for details of valid arguments and
     keyword arguments.
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
     axes = kwargs.get("axes")
     result = iplt.fill_between(x, y1, y2, *args, **kwargs)
@@ -330,6 +372,11 @@ def hist(x, *args, **kwargs):
 
     See :func:`iris.plot.hist` for details of valid arguments and
     keyword arguments.
+
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
     axes = kwargs.get("axes")
     result = iplt.hist(x, *args, **kwargs)
diff --git a/lib/iris/util.py b/lib/iris/util.py
index d2af4c1085..7900b734a8 100644
--- a/lib/iris/util.py
+++ b/lib/iris/util.py
@@ -70,6 +70,11 @@ def broadcast_to_shape(array, shape, dim_map):
         # a is an array of shape (48, 96)
         result = broadcast_to_shape(a, (96, 48, 12), (1, 0))
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     if len(dim_map) != array.ndim:
         # We must check for this condition here because we cannot rely on
@@ -142,6 +147,11 @@ def delta(ndarray, dimension, circular=False):
             >>> iris.util.delta(original, 0, circular=360)
             array([90, 90, 90, 90])
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     if circular is not False:
         _delta = np.roll(ndarray, -1, axis=dimension)
@@ -192,6 +202,11 @@ def describe_diff(cube_a, cube_b, output_file=None):
         two cubes will merge requires additional logic that is beyond the
         scope of this function.
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
 
     if output_file is None:
@@ -244,6 +259,11 @@ def guess_coord_axis(coord):
     Returns:
         'T', 'Z', 'Y', 'X', or None.
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     axis = None
 
@@ -305,6 +325,11 @@ def rolling_window(a, window=1, step=1, axis=-1):
         array([[ 1.,  2.,  3.],
                [ 6.,  7.,  8.]])
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     # NOTE: The implementation of this function originates from
     # https://github.com/numpy/numpy/pull/31#issuecomment-1304851 04/08/2011
@@ -359,6 +384,10 @@ def array_equal(array1, array2, withnans=False):
     This provides much the same functionality as :func:`numpy.array_equal`, but
     with additional support for arrays of strings and NaN-tolerant operation.
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
 
     def normalise_array(array):
@@ -407,6 +436,11 @@ def approx_equal(a, b, max_absolute_error=1e-10, max_relative_error=1e-10):
        if the actual error equals the maximum, whereas :func:`util.approx_equal`
        will return False.
 
+    Notes
+    ------
+    This function does maintain laziness when called; it doesn't realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     wmsg = (
         "iris.util.approx_equal has been deprecated and will be removed, "
@@ -456,6 +490,11 @@ def between(lh, rh, lh_inclusive=True, rh_inclusive=True):
         for i in range(10):
            print(i, between_3_and_6(i))
 
+    Notes
+    ------
+    This function does maintain laziness when called; it doesn't realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     if lh_inclusive and rh_inclusive:
         return lambda c: lh <= c <= rh
@@ -510,6 +549,11 @@ def reverse(cube_or_array, coords_or_dims):
           [19 18 17 16]
           [15 14 13 12]]]
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     from iris.cube import Cube
 
@@ -588,6 +632,11 @@ def monotonic(array, strict=False, return_direction=False):
 
             ``(monotonic_status, direction)``
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     if array.ndim != 1 or len(array) <= 1:
         raise ValueError(
@@ -640,6 +689,11 @@ def column_slices_generator(full_slice, ndims):
     This method was developed as numpy does not support the direct
     approach of [(3, 5), : , (1, 6, 8)] for column based indexing.
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     list_of_slices = []
 
@@ -1035,6 +1089,10 @@ def clip_string(the_str, clip_length=70, rider="..."):
         If the clip length was greater than the original string, the
         original string is returned unaltered.
 
+    Notes
+    ------
+    This function does maintain laziness when called; it doesn't realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
 
     if clip_length >= len(the_str) or clip_length <= 0:
@@ -1065,6 +1123,11 @@ def format_array(arr):
 
     For customisations, use the :mod:`numpy.core.arrayprint` directly.
 
+    Notes
+    ------
+    This function does maintain laziness when called; it doesn't realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
 
     summary_threshold = 85
@@ -1095,7 +1158,7 @@ def format_array(arr):
     return result
 
 
-def new_axis(src_cube, scalar_coord=None, expand_extras=()):
+def new_axis(src_cube, scalar_coord=None, expand_extras=()):  # maybe not lazy
     """
     Create a new axis as the leading dimension of the cube, promoting a scalar
     coordinate if specified.
@@ -1128,6 +1191,11 @@ def new_axis(src_cube, scalar_coord=None, expand_extras=()):
         >>> ncube = iris.util.new_axis(cube, 'time')
         >>> ncube.shape
         (1, 360, 360)
+
+    Notes
+    ------
+    This function does maintain laziness when called; it doesn't realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
 
     def _reshape_data_array(data_manager):
@@ -1245,6 +1313,11 @@ def squeeze(cube):
         >>> ncube.shape
         (360, 360)
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
 
     slices = [
@@ -1314,7 +1387,14 @@ def file_is_newer_than(result_path, source_paths):
 
 
 def is_regular(coord):
-    """Determine if the given coord is regular."""
+    """
+    Determine if the given coord is regular.
+
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+    """
     try:
         regular_step(coord)
     except iris.exceptions.CoordinateNotRegularError:
@@ -1325,7 +1405,15 @@ def is_regular(coord):
 
 
 def regular_step(coord):
-    """Return the regular step from a coord or fail."""
+    """
+    Return the regular step from a coord or fail.
+
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
+    """
     if coord.ndim != 1:
         raise iris.exceptions.CoordinateMultiDimError("Expected 1D coord")
     if coord.shape[0] < 2:
@@ -1356,6 +1444,10 @@ def regular_points(zeroth, step, count):
     count : number
         The number of point values.
 
+    Notes
+    ------
+    This function does maintain laziness when called; it doesn't realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
     points = (zeroth + step) + step * np.arange(count, dtype=np.float32)
     _, regular = iris.util.points_step(points)
@@ -1376,6 +1468,12 @@ def points_step(points):
     -------
     numeric, bool
         A tuple containing the average difference between values, and whether the difference is regular.
+
+
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
     """
     # Calculations only make sense with multiple points
     points = np.asanyarray(points)
@@ -1405,6 +1503,11 @@ def unify_time_units(cubes):
     * cubes:
         An iterable containing :class:`iris.cube.Cube` instances.
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     epochs = {}
 
@@ -1545,6 +1648,12 @@ def promote_aux_coord_to_dim_coord(cube, name_or_coord):
                 forecast_period                  x              -              -
                 time                             x              -              -
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
+
     """
     from iris.coords import Coord, DimCoord
 
@@ -1671,6 +1780,12 @@ def demote_dim_coord_to_aux_coord(cube, name_or_coord):
                 time                            x              -              -
                 year                            x              -              -
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
+
     """
     from iris.coords import Coord
 
@@ -1762,6 +1877,12 @@ def find_discontiguities(cube, rel_tol=1e-5, abs_tol=1e-8):
         # Plot the masked cube slice:
         iplt.pcolormesh(masked_cube_slice)
 
+    Notes
+    ------
+    This function does not maintain laziness when called; it realises data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
+
     """
     lats_and_lons = [
         "latitude",
@@ -1903,6 +2024,10 @@ def mask_cube(cube, points_to_mask, in_place=False, dim=None):
 
     If either ``cube`` or ``points_to_mask`` is lazy, the result will be lazy.
 
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
+
     """
     if in_place and not cube.has_lazy_data():
         # Ensure cube data is masked type so we can work on it in-place.
@@ -1949,6 +2074,11 @@ def equalise_attributes(cubes):
     * removed (list):
         A list of dicts holding the removed attributes.
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
     """
     removed = []
     # Work out which attributes are identical across all the cubes.
@@ -1992,6 +2122,12 @@ def is_masked(array):
     bool
         Whether or not the array has any masks.
 
+    Notes
+    ------
+    This function maintains laziness when called; it does not realise data.
+    See more at :doc:`/userguide/real_and_lazy_data`.
+
+
     """
     if is_lazy_data(array):
         result = da.ma.getmaskarray(array).any().compute()
@@ -2008,7 +2144,6 @@ def _strip_metadata_from_dims(cube, dims):
 
     To be used by operations that modify or remove dimensions.
     Note: does nothing to (aux)-coordinates.  Those would be handled explicitly by the calling operation.
-
     """
     reduced_cube = cube.copy()