Anal passing 

Anal passing is where two people put the ends of their asses opposite each other and stretch it widely so that when one of them poops, the poop goes into the other's ass and they keep passing it around.

The two students got caught anal passing and were expelled

Anal passing by OfficialChocolateBar September 1, 2021

anal pissing 

the act of urinating while your cock is in a woman's ass

That freak was totally into anal pissing

anal pissing by cilicat February 12, 2010