(vulgar) The sexual practice of fisting.

present participle of fist-fuck

(vulgar, slang) sexual practice in which a (fisted) hand is inserted and moved in or around the vagina or rectum.

(vulgar, slang) To insert and remove and move a (fisted) hand in someone's vagina or rectum.

Third-person singular simple present indicative form of fist-fuck

simple past tense and past participle of fist-fuck