it's the kind of face a person makes when someone says something utterly stupid, or when you drop something after you were trying so hard not to. It's like a "WHAT THE HELL" face.
You can also say it whenever something dumb happens. It's kind of like a "okay no" sort of face, you know? Everyone makes it a lot, they just never know it's a jface ;)
sort of like this: =_=
Person 1: I made up a new wordtoday!
Person 2: Cool, what is it?
Person 1: Squinkle.
Person 2: ...jface.
Pronounced, yaf-cob. Jafcob is the act of a lover sticking a raw corn cob into the others anus. The cob is then left for up to an hour and is cooked by the heat of the anus. The corn is then rendered off the cob and eaten by the lovers.
Hey babe lets do jafcob for dinner tonight.
Did you hear that the neighbors are into jafcob?
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.