Hi Harron
Now I understood this trick.
If you want to create an irregular shadows for a pear or bell. you cannot use linear gradient or radial gradient. because the shadow has to follow the shape of the pear.
you can use the mesh tools. but this trick is easy and for rapid work.
1 draw your shape for shadows and choose its color.
2 go to effect > Stylize> feather the shape become smooth in its border.
3 take the mother shape of the pears that you want to adds this shadow
4 put the pears shape in the front and choose white color
5 go the transparency palette and select the shadows shape and the pear shape and choose > Make Opacity mask from the transparency palette.