a "permanent grin" which one can only achieve through being in a totally different dimension (usually through use of peyote, lsd, and is definitely popular with shrooms)
guy1: so herd everyone went trippin this weekend, how was it?
guy2: it was great, everyone was real chill, paul's dumbass had a stupid perma grin that he couldnt wipe off and he didnt say shit the whole time. Hes such a sleezebag.
An automatic and irremovable smile that appears on the face of people who are thoroughly intoxicated with some narcotic; usually marijuana, hashish, mushrooms, or lsd. Can be found in other cases such as on television morning news anchors, beauty pageant contestants, pop queens, and mental patients.
"Look at Greg! Dude has Perma-grin! That must be some good shit!"