leaky sheiky
Derived from the condom brand 'Sheik'. An expression used to describe a faulty or defective condom that, due to (usually unconcious) puncturing or size problems, well, leaks during intercourse. Usually used in conjuction with a girl getting knocked up.
"You really should get a vasendectomy, one day that leaky sheiky is going to come along and you two will be screwed"