blue knob
a male who is tight with money, aka a tight fisted wanker.
Chris Wakelin
Door Knob Blue Balls
When you're on your way to getting laid but then the girl hears the sound of a door knob and she is suddenly freaked out and you know there is no way you're getting her back into the mood.
"She was just sliding off her panties when her parents got home and she heard the front door knob. There was no way she was putting out after that. Nothing sucks worse than door knob blue balls."