The impoverished form of an Irish Car Bomb (Bailey's dropped into and chugged from a Guinness). A head on collision is Kahlua dropped and chugged from a Busch Light.
1) Serve a shot of Kahlua
2) Drop into a cup of Busch Light
3) Chug in one gulp
"-Yo, let's do an Irish Car Bomb.
-Nah, that's too classy, I'll take a head on collision"
(Def. 1): A popular method of intimidation in ancient history; where the winning army cuts off the heads of defeated soldiers, impaling them on a pike or stick to demoralize and frighten the conquered people. It was also used after an execution to make a public example of the consequences of breaking the law.
(Def. 2): A metaphor describing retaliation or punishment for another's wrongdoing, or public outrage against an individual or group for the same reason.
After the BP Oil Spill; many Americans would like to see Tony Hayward's head on a stick, myself included.
A sign of affection when one rests their head on their mate's shoulder. This can be a big first step to a more physical way of showing affection in a relationship.
"Hey guys She finally got to put my head on shoulder"
"Wow congratsman!"