A sex move where one person shoves a basketball into another persons ass.
Steve: I gave my gf a Slam Dunk In The Trunk last night!
Bruce: Wow you fit the whole ball in there?
Steve: Yeah I made it work.
After you’ve used all 10 of your fingers to get a single woman to climax
Jane glowed and exclaimed “Tom gave me the 10 finger dunk and knocked the cobwebs out last night.”