shadow1337's definitions
Giving an instant orgasm by quickly jabbing one's sides near the kidney on one or both sides at once which causes involuntary movement and sometimes unnecessary noises...
Boy 1: I'm going to give that kid an insta-gasm guys...
Boy 2: (After he was given the insta-gasm) (yelling) IT'S SO INSTANT!
Boy 2: (After he was given the insta-gasm) (yelling) IT'S SO INSTANT!
by shadow1337 May 23, 2009
Get the insta-gasmmug.