When a guy has inserted his penis into his partners vagina for the first time, but doesn’t cum. He is considered a half-virgin because he hasn't fully experienced sex.
I almost lost my virginity, but I just couldn't cum, at least now im only half-virgin.
Kate : you're still a virgin?
Michelle : I'm a half-virgin. I'm gay, so I haven't had the whole "penis" experience. Nor do I ever plan to.
Kate : Ha-ha. Oh.
A sunburn or suntan focused on the left arm. It is caused by the left side of the body being the only half that gets exposed to sunlight while driving. Presumably, it would be located on the right side of the body in countries where they drive on the left side of the road.