A man who receives anal sex and allows the other man to shoot a load (or two) inside him, then saving it in his anus. He then goes home to his lover and fucks him in the ass with the other guys cum still in his ass. The cum jockey is probably high on crystal meth, thus allowing this minor lapse in judgment over what is in good taste and what is not. He, however, finds great pleasure in the fact that he is still full of jizz. This must take great muscle control and a true deviant piggy mind.
John is a total Cum jockey! Bill filled his hole twice before he went home to Steven. What a weird way to have a 3-way!
After a very tall man has sex with a male or female horse (the man taking part in the role of the "giver"), he takes his dick out of the horse's asshole/vagina and sprays his cum on top of the horse's back. Before a horse race will begin, the lucky horse jockeys will notice said stain, and hence refer to the stain as a "Cum Jockey". The unlucky ones will place their saddle on top of the Cum Jockey, thereby causing the Jockey to slide around and be imbalanced during the horse race due to the lubrication effect of the sperm.
Jockey 1: Hey Fred, don't sit on Seabiscuit just yet! It may have a Cum Jockey on it.
Jockey 2: This must be the work of... Tall People! >:O