Mongolian Teabag
The act of dropping ones testicles in anothers gaping anus. After the testicles have been inserted the receiver then tenses their anus and the giver pulls their testicles out of the now closed anus, making a loud wet pop.
Dude, I gave your mum the meanest Mongolian Teabag last night, still have the shit on my nuts to prove it too.