an orgasm in your mouth.

(adj) An adjective concatenation of oral and orgasm used to describe the intensely pleasurable sensation produced by the experience of tasting, eating, or otherwise introducing something to one's mouth. Oralgasmic experiences are often characterised by a closing of the eyes, swooning, salivation, and appreciative noises.

It's what happens in your mouth when you drink something you weren't expecting.

When you eat something so delicious, that your mouth just starts gushing liquid, like gleeking everywhere.