>>8507610As a fat guy, I can answer this. It's the belly. If you pull your pants up to your navel, your gut will push the pants down when you sit. This also leads to pulling your pants up constantly. If you belt to under your gut, your pants stay up but your asscrack is exposed. Most fat guys don't hold themselves to much of a standard anyways so they let their asscracks breathe. Personally, my mom used to shame my brother and me about it so I'm very self conscious to not let my asscrack be exposed. My brother though, that guy will have his asscrack out while walking with shit smears on display. That guy don't give a fuck and he's seen as more likable than me even if I won't leave shit smears on your furniture.