When performing fellatio and a hair, generally a pubic hair, enters the fallatiater's mouth. Occasionally the hair will get snagged between the victim's teeth causing significant irritation. Another typical scenario includes the hair sticking to the tongue, often precipitating a half-cough/half-gag reaction similar to a cat coughing up a hair ball.
"Ugh, I always get head hair when I blow Tommy. I wish he'd trim his pubes."
It is when you get head (blow jobs), for the rest of your life from someone. It usually comes up from a crazy bet to win a football game or something else stupid.
Bristol: we are going to lose
Pat: no we're gonna win.
Bristol: ...we re gonna lose
Pat: okay well if we win then you owe me head for life, and if we lose then ill buy 50 cheeseburgers from McDonalds.
Bristol: okay fine 20 min later and after the team wins
Bristol: fuck
Pat: haha hell yeah
A wager between lovers where the winner of the bet receives oral sex from the loser. Wagering a head bet can create excitement around an otherwise uneventful activity. Really, both are winners in the wagering of a head bet.
My girlfriend and I wagered a head bet on who would be the first to spot an attractive person shopping at our neighborhood Wal-Mart Supercenter.