Generally under my belly hang, I find it more comfortable and less restrictive to have my belly hang over. I just have to make sure I get long enough tshirts to cover the gut😉. Also my fat pad tends to fill the crotch of my jeans.
I used to put it over my belly, but as I gained weight recently I prefer it to be under. It’s really uncomfortable otherwise, if my belly is visible so be it. I prefer to feel comfortable.
I prefer to wear mine under my ball belly so it accentuates it :-) My wife stopped wearing underwear years ago because she simply got too fat for it to be comfy. She wears hers midway up her double belly, mainly to keep up the crease separating upper from lower :-)
