A somewhat uncommon medical condition in which the afflicted party is hopelessly addicted to any of the butthole pleasures.
John was diagnosed with a severe case of buttsexitis, but he kept claiming that it was not about the butthole pleasures.
It means you put the penis in the ass. Duh?
"Our Buttsex was good last night! Wasn't it Kaitoo?" Riely asked
1) taking it like a man, in the behind.
2) doing wrong to someone, like backing into their new convertible and not leaving a note.
I totally buttsexed the shit outta that guy!
this fits both definitions.
A "savory" treat selfish women like to reserve for special occasions
John put his penis in and out of Edd's butt, real hard an fast. They had buttsex.
putting a penis into someone's anus
serge loved buttsex a whole lot, especially with his guy friends