A guy/girl who becomes the test subject in a relationship. He/she had a crush on you, without knowing that you're just wanna play around with him/her. Usually ends with the guy/girl being dumped.
Watch the movie 'How To Lose A Guy In 10 Days' to get better idea
Guy #1: That jock at school just wanna have fun with one of the cheerleaders. He doesn't intend to have serious relationship with her
Guy #2: Too bad the girl still fell in love with him Guy #1: Oh well, there goes another crush test dummy
During anal, stand on the edge of the bed with your penis head barely inserted into her ass. Then fall forward to the floor and the rest of it goes in. (best to make her wear a mouthpiece so her teeth don't get knocked out.)