Rubbing/holding/masturbating two penises together for sexual pleasure. Usually, both men stand or lie down facing each other so that the undersides of both penises touch along their entire length, allowing one person to masturbate both penises simultaneously.

The warmth of the other penis and the added stimulation from contact along the entire length of the shaft can create increased sensation compared to ordinary mutual masturbation (hand only). A finger inserted between the heads of the two penises will be lubricated by the combined pre-cum and may cause additional stimulation.

Also may be performed by holding together two penises which face opposite directions (side-by-side or one on top of the other), or by lying down in opposite directions .
"I don't like anal because when you pull out it gives you shitdick. I prefer frotting."

"My bro Jake and I give each other HJs sometimes when we're blue balling, but I tried frotting with him last night and came buckets!"
by WhiskeyAndCigarettes May 28, 2012
Rubbing one's crotch against unexpecting people, furniture or walls. A favourite of sex-starved Japanese businessmen on the sub-way.
I caught him frotting the fridge once, it was just wrong.
by bogun_420 June 23, 2003
Whilst riding a large touring motorcycle,

crotch rubing and pelvic thrusting the 'horn' (large padded area at front of motorcycle seat). Sometimes for a sexual reason.
Riding my motorbike just frotting and cruising, cruising and frotting.
by WERD dd November 11, 2017
A sexy act between two men that involves them being naked, and rubbing their penises together.

It can involve one's hand, trying to bring the two together for pleasure, but isn't always a necessity in the act.

Josh frotted with one of his frat brothers last night. It was sensual.

by darksongbird March 21, 2009
actual, factual, real deal, no-girls-allowed, sex between men, rubbing penises together between two humping bodies or within a single hand
I wanna frot you like an animal.
by Guy April 25, 2004
When two men rub penises together in an attempt to start fire.
"The home of Lord Homosexual was burned down last night. One witness said they were frotting when the bed caught on fire, even though the bed was supposedly fire resistant.
by TreuMinkzx March 19, 2015