2. when someone comes up behind you and shoves their knee up your ass.
2. You fucker! Stop camel humping me!
It's when a guy where's really tight pants or something and you can see the shape of his balls; therefore looking like camel's humps. nice and lumpy.
Yeah, it was infested with camel humps.
Requires one pair of running shorts and some frank and beans. Now pull the shorts up real high and give yourself a wedgie. Look down at your crotch and--voila! Camel hump!
"Oh shit, here comes coach!"