To stare at someone in a creepy, sexual way, usually for several minutes without blinking or stopping when the person being eye-humped realizes he/she is being mentally undressed (and doesn't even want to think what else) by the eye-humper. If done right, very unnerving.
"Elmo likes to eye-hump you!"
by Natepalm October 19, 2003
to think about fucking a woman while looking at her
Hey Jim! Stop eye humping my wife!
by Anonymous April 08, 2003