tongue-fuck means for a guy to fuck a dude's butt-hole with his tongue as deeply as he can - trying to make the guy have a cumgasm - the dude may or may not be jacking off or sucking a dick.
That dude has such a cute boy-hole, why don't you have him suck your dick while I tongue-fuck his asshole until he cums!
1. To use the tongue to suck and enter the asshole of a partner before anal intercourse. The tongue is often repeatedly jabbed at the asshole to relax and open the ass ring.
2. To use the tongue to suck and enter the asshole of a partner after anal intercourse. Used as a method of extraction of semen and other fluids from the rectum. See felch.
Tom tongue fucked his buddy's tangyasshole and reclaimed his load of cum.