To suck air into the asshole and then fart it out. When one who has the ability to gain does this, it makes a strange sucking noise as they draw the air into their bunghole.
by Bitches Brew August 10, 2003
Get the gainmug. 
phil : i had sex with a female last night
Maxx: soo much gain for you
Rob: i ate a whole big mac today
Samantha: Gain on you
Caddy: i sucked some mean dick last night
pimp: GAIIIIIIIINNNN!
Raphael: i scored the winning goal last night
George: Gaintastic!!
Maxx: soo much gain for you
Rob: i ate a whole big mac today
Samantha: Gain on you
Caddy: i sucked some mean dick last night
pimp: GAIIIIIIIINNNN!
Raphael: i scored the winning goal last night
George: Gaintastic!!
by icallquest August 19, 2008
Get the gainmug. (Slang) Derogatory term used to describe disease and sick people. “Gains” people are very diseased or ill. If you have “gains” you have a terminal illness.
by sosisidaa June 14, 2019
Get the gainsmug. Gaine:
1.Derived from the word Gay
2.a soft fellow hailing from new England but roots prodominitly for New York teams, most importantly the Yankees.
3. Born with 3 testicles
1.Derived from the word Gay
2.a soft fellow hailing from new England but roots prodominitly for New York teams, most importantly the Yankees.
3. Born with 3 testicles
by Johan Martin October 30, 2007
Get the gainemug. Defines a man with Big Dick Energy
by startupthanos September 20, 2018
Get the Gainsmug.