Laughing, abnormally and uncontrollably, due to the consumption of Marijuana.
Laughter is often accompanied by tears and occurs, most often, in the early stages of one's relationship with Marijuana - with instances becoming fewer with (smoking) experience.
Often while geeking out, one's abdominal muscles will begin to cramp and his friends will either try to prolong the geek session by being randomly funny or become extremely annoyed.
Pud: Are you guys going to be smoking Marijuana all night?
Rouw: Yeah man, this is some good shit.
Mule: Hell yeah... I need to squat down. I just ate that half-pound ben's burger in 36 seconds.
Snood: hahahahaaha!!!!! hahahahahaha!!!!
Rouw: Damn, snood's geeking out! Stop geeking snood!