Vomiting
From Voyeurweb's Wiki about Sex
Vomiting means to purposefully or unintentionally expelling the stomach contents through the mouth (and occasionally nose, very bad if having just eaten spaghetti) :0)
People vomit because of excessive alcohol intake, sickness, swallowing too much cum or as a very poor choice in weight loss methods.
There is quite possibly a fetish here somewhere but I don't really want to go there :0)