When a girl is having non-committal unprotected sex informing the man he can pull out at the instant before ejaculation. When the male informs the female of the pull out she instead wraps her legs around him forcing his man juice inside of her, causing his penis to be trapped in her 'lobster'.
Matt: Man how did you end up having Aubrey as a baby mama?
Joe: She gave me a Newfoundland lobster trap the night I met her at the bar.
Originating from an episode of How I Met Your Mother where they discussed multiple Canadian sex acts, the Newfoundland lobster trap involves a girl having sex on top of a guy, and right when he is about to climax, he twists her nipples and yells "Here comes the drawn butter!"
Last night, I ran out of sex acts to perform so I had to give her a Newfoundland lobster trap!