while getting a blowjob, just before orgasm slap her on the back of the head driving the penis down her throat. she can't bite down while gagging, and she tries not to swallow so there is only one place to come out...her nose. throw her a towel and tell her to clean herself up then RUN. when she gets done blowing the jiz from her nose and the tears from her eyes she is gonna want to kill you.
The perfect way to get yourself out of a bad relationship with a two bit whore is by giving her the snapdragon.