the act of spreading ones ass cheeks and farting, producing a cloud of rancid ass instantaneously making the room smell like queen latifah's queef.
While Jake was sleeping, Bogart violated his face with insta-stink. =^.^=
When any person rips a fart in front of a fan (rotating preferred) while an unexpecting person in the room with you gets to enjoy that sweet sweet anal vapour, hence insta-stink cause it instantly stinks.
While laying in bed with our fan blowing on us I ripped a rather large fart and the insta-stink went up my girlfriend's nose. Who needs the old fashoned dutch oven when you can use this perfect odour enhancer.
When one's fart is so volatile that the instant it is released it stinks up the room. Also known as "immediate stink".
Alex: I just farted, and I would re-locate NOW because it just may be an insta-stink!
Sarah: ::is already running away::