How many wear slips under their skirts and dresses? Do you like wearing them?

I've been finding that my skirts and dresses, especially the long, flowy ones, will get stuck between my legs when I'm sitting and I'm wondering if a slip will help keep my skirts and dresses from showing the back of my legs because of getting stuck between then.

A slip is a required part of a skirt system.  As you found, it is a necessity for proper skirt control.  Some skirts have a slip (liner) built-in, but other skirts need one as an accessory.  The only time I don't wear a slip is on a very hot day, with a skirt that is short enough not to need one.

I certainly do wear slips.