Blowing a stop sign 

When during heavy petting and foreplay between a man and a woman, when the man's hand goes up her thigh to her crotch region, she gently puts her hand against her thigh to gently block his hand. That little gesture by the woman is her "stop sign" meaning "Stop". A good guy will take the hint and stop.

Brian was a good date, he did not end up blowing a stop sign.

Hey Jeff, I was being a good date, we started with some heavy petting, and I tried to get to her goodies. She blocked me with her hand. I was a good guy, I did not blow her stop sign.

Blowing a stop sign by Trottenheimer March 6, 2008