A culinary-induced orgasm, usually requiring a post-mastication cigarette to intensify the effect.
1) Geoffrey: "Those crab puffs made me make white in my pants!"
Chuck: "Oh, you just experienced a gastrogasm!"
2) Even if my girlfriend cooks naked and gives me head, her food never gives me a gastrogasm.
The sensation you have when eating large amounts of exceptionally delicious and extremely decadent cuisine. Basically, an orgasm brought on by eating great food.
Man, that risotto is soooo good, I'm having a gastrogasm.