When the girl is laying on the bed naked and the man spreads her legs and keeps them wide open, then proceeds to fuck the living the shit out of her. The combination of spread legs and bent arms creates the illusion of a 3-pointed star. If you don't believe me, I highly encourage you to walk down to the nearest corner, pick up a hooker, and proceed to fuck her brains out. You're welcome.
Person A: "Dude, last night Jenay and I fucked like wild monkeys!"
Person B: "No shit?! Atta boy, you guys screw doggy style like always?
Person A: "Well first we had the face-fucking, then we did The 3-pointed star, my cock felt like a meteor shower."