when with a female partner, the man must be very sly if he wants to correctly perform the japanese star. before having sex, put a bottle of Sriracha hot chili sauce next to the bed. then, while getting intimate with your girl, secretly cover your hand in the sauce. make sure she doesn't see this. then, in one swift motion, shove your fist into the girls vagina and spread your fingers out. this will create a spicy, burning, probably painful sensation for the girl.
Jamie: " Dude, how was your night with Kayla?"
Nick: " eh, i japanese star'd her"
Jamie: " oh god. how'd it end?"
Nick: " shes dead"