When a person takes a plastic bag and puts a target on it with a marker. Then proceed to put the bag over your head and then keep it on with a belt tightly around your neck. After you have done this begin to Masterbate (Fap). When your about to Ejaculate (Cum) aim for the target you have drawn on your plastic bag. if you hit the bullseye you win.
I would not do the jellad on a plane, i might break my neck.