"fist on" is something fellow fisters say to each other, as a form of encouragement and also when a fister is leaving you say "fist on" to encourage them to keep fisten and if the fister is polite he/she will reply back "by the fistfull!". It creates good vibes and makes people feel happy and fruitfull, by the fistfull!

Fighting with no weapons, fist to fist.

The ultimate weapon of ass destruction. See fisting.

to insert ones fist into another individuals vagina or anus

the act or art of putting a fist in an ass or vigina, very popular practice among more evolved(kinky)gays. requires great care and huge amounts of lubrication

A male or female getting a fist shoved up there ass till they cry getting fisted feels good actually

v. To insert a fist into someone's vagina or anus, presumably, to give them pleasure.

What you do if you have a small penis.