Guy is standing up. Girl is in front of guy, on her knees giving him head. Right after the guy blows his load, before she can swallow it, he smacks her under the chin causing her head to raise up. Then punches her in the gut so she spits the load out. Kinda like when you lift the head on a real PEZ Dispenser and candy comes out. For added realism and fun have the girl ware some sort of Halloween mask, like Darth Vader or Bugs Bunny, etc.
At the Halloween party I went in the bathroom with this chick in a Yoda costume and did a PEZ Dispenser.