To perform doggy style sex with a partner who does not want to recieve a facial cum-shot, so when you are going to ejaculate you pull out, spit on the partners back to fool them into thinking you've finished. Then, when they turn around, you blow the load onto their face.
Guy: (Faking orgasm noise:: spits)
Girl: (turns around) was that good
Guy: (blows load onto surprised girl) You just got sticky hitlerd beeyatch