Do any of you guys use waist trainers, and if so, when do you use them?

Every night before I go to sleep (I've worn one for approximately 2 years), I put on a waist trainer; in the morning, I take it off.

I find it helps even though I wear an XS waist trainer. It used to help with my stomach pains from hunger (when I got them, I used to starve myself so much that the pains were greatly reduced)

furthermore providing me some shape (even though I know it's transitory)

My body is really straight by nature.