1. Noun: A girl/boy who stops strokingthe meat RIGHT when you are about to cum. This term only applies to a Handjob/Blowjob but only when the orgasm is ruined.
Alex: Hey dan your mom is a cock stopper! She stopped suckin RIGHT when I began to shoot it and it ruined my orgasm.
1. Finding out the "woman" you are bedding has a penis. In all but 1% of men this is known to stop the cock dead in it's tracks returning to it's flaccid form.