When a female performs the act of sitting (i.e. straddling) on a males mouth, nose, and/or general facial area. Men "teabag" women, usually on the forehead, but not contained only to that area, while women "lunchmeat" their male counterparts. In other words, if you opened a package of sliced lunchmeat and shoved your face into the side, you'd essentially be replicating this act.
DUDE!! Last night after I woke up your sister, teabagging her in her sleep, she totally woke me up this morning laying that lunchmeat on my face!! I ate that pussy like grade A roast beef! U mad bro?