"straight"
Close your eyes, start jerking off your cock, lean forward and lick your mousepad (or whatever cloth you have around)
Imagine very hard that what you are licking is the
scrotum of your boss, while he fucks your girlfriend in the ass. But don't cum, just get to the edge and then stop, slap your cock hard once, and think about how pathetic you are.
Edit: Oooops, I didn't realize this was so old. Jeeeez this place needs more people like me.