consuming an alcoholic beverage shot
that has been poured down the lower back of your bud/girlfriend, catching it in your mouth just before it descends into his/her butt crack. Exemplified by US embassy security in Kabul, Afghanistan.
Dude 1: Did you see Josh take a moon shot off Wes?
Dude 2: Yeah, he was a little low on the intake, and caught a dingleberry