OK. Where,exactly,do you put the silcone grease?

In a piston filler, it is widely said that to keep the piston movement smooth, 100 percent silcone grease should be used from time to time. So where, exactly, do you put it? Say you remove the nib and feed by unscrewing it from the section. Now you have access directly to the piston and to the sides of the reservoir that holds the ink. Some say the amount of grease to apply is merely that that dance on the head of toothpick. But-- Where do you apply the grease? To the flat surface of the piston? To the sides of the cylinder that is holding the ink? Thanks--

Inner sides of the body where the seal touches. Apply sparingly then run the piston up and down to distribute the grease. If there is any excess it should be removed so that there is no chance any could get into the feed.

Thanks!