While fucking a girl from the back in a room with two windows face one with your back to the other. have a friend climb in through the window to your back and switch with him. proceed to climb out the window and wait for your friend to bust his load. as he does, pop up in the other window and wave to the girl with a big smile on your face.
Man, Mark and i totally pulled a magic show on Steph last night. The look on her face was priceless.