That moment when you wake up, usually hanging from a night on the lash, to sunshine and a foot of fresh pow, causing you to violently jizz in your pants.
This can also occur when watching skiporn, before you shred a line, whilst shredding a line or when you see an absolutely bangtastic female skier.
Skier #1: Mate, look out the window, it's fucking fantastic
Skier #2: Oh my fucking god...I'm pretty sure I just had a skigasm
Skier #1: Let's go shred that shit