Not to be confused with "Buzz-Kill"
friend - "dude it looks like someone hit your car"
friend 2 - "Talk about a Boner Kill"
When someone shares information you didn't want to know, especially if the person is of the opposite sex. When a girl, who initially was turning you on, turns you off by, for example, giving you hand backwards or getting tired and giving up. Also used to express general disgust.
"Well Stef, everything was fine. She was giving me hand and then she kinda just... got tired, slowed down and kind of... stopped... it was kinda like losing power in the middle of a hockey game... what a boner-kill."
"I think I'm gonna cry."