This hilariously tragic sex prank is achieved through the following: You begin normally having sex, you then tell her to get on all fours (Doggystyle), all the while covertly aiming her towards a window, immediately after, your friend will come and switch places with you. Then, you will calmly walk past the window, then turn and wave at your misguided partner.
Dude: OMG MAN, MEMBER THAT BITCH JULY?
Dude: Me and Man totally pulled a Canadian Border Patrol on her.
Guy: Dude... you're fucked up... In a funny kinda way!