One who behaves in a particularly obnoxious or selfish manner; as though they have cum for brains. A jerk.
Tom ate the last of the fuck'n cheese again, and he hasn't been to the store in over a month, that dick head!
Girl: Are you still dating Simon?
Another Girl: What the fuck! I thought he was cool at first, but that asswipe stood me up twice in a row and never called again!
Girl: What a dick head!
Dick snot is indeed semen but is more accuratley used when referring to jism dribbling from the eye of the penis (as opposed to shooting) as regular snot does from the nose when you have a cold.
After releasing a generous wad of ball-sack bolognaise into the eye of my girlfriend, she gleefully slurped the remaining dick snot from the head of my penis.