by Steelson Jeffflex October 22, 2013
The act of multiple men sodomising eachother in a human train. Just before ejaculating each one pulls out and blows their load all over the back of the guy in front shouting "twenty-one !"
by DamienN July 14, 2006
Verb
1. The act of rubbing ones self to ejaculation within the rolls of their partners back fat. Similar to a reverse titty fuck.
1. The act of rubbing ones self to ejaculation within the rolls of their partners back fat. Similar to a reverse titty fuck.
"I brought some fat broad home from the bar last night. I couldn't find her vagina, so we started backjacking instead."
by billebllunt December 9, 2013
The act of traveling across country, sperm bank to sperm bank, funding your travels with your ejaculate
by Nero1313 October 2, 2015
by BOBBLE BOO October 19, 2007
A form of masturbation where you slide your hand down your dick with your hand backwards, forefinger and thumb touching eachother. Your thumb should be facing in twards your balls and your pinky out twards the head.
Painting a face on your hand is optional.
Painting a face on your hand is optional.
by Clam Choder April 25, 2007
The act of jacking off your boyfriend whist he is sat behind you as you are typing this onto his laptop at the same time. During this he is sitting on his Nintendo DS playing Pokemon.
Example: having a laptop on your knee; sitting on the end of the bed; penis in hand! There you have, a backjack!
by Carrots. June 29, 2014