What is Detroit Dumbell?
1.
Having vaginal sex with a girl then shoving it in her anus and hitting her in the back of the head with a dumbell once she starts to scream, thus knocking the girl unconsious so the man can have peaceful anal sex.
Joel: Dude, I hooked up with Jen last night. She's never been into anal sex.
Billy: How'd you get her to do it, man?
Joel: Simple. I gave her the Detroit Dumbell once she started to scream.
See