Bumbumming 

(verb) To rub your bum against someone else's bum

I was bumbumming my partner and we were aroused

Bumbumming by TheBigPoke November 23, 2022

bumcuming 

When your gay sexual partner sperm dribbles out of your anus after anus intercourse

Dave..I think I've just pissed out of my ass
John.. No its just ur bumcuming. Or should I say my cum out of ur bum
Dave.. Well least I won't get pregnant

bumcuming by mitch00uk April 10, 2015