To lift one’s leg in the air, like a cat, and reveal one’s butthole. Often done spontaneously and to surprise others. Requires flexibility to lift one’s leg nearly vertically. See film Cats (2019) for reference.
Girl to friend: Can you believe Britney?! She just Judi-Denched herself and then kissed her boyfriend. Iconic.
Chad: Bro, I met this girl on Tinder that wants to watch me Dench. Should I go for it?
To hedge your bets by hitting on everyone/thing at a party. This is to ensure that at the end of the night no matter how drunk you are you have someone to go screw. Derives from "dutching" which means to place mulitple bets on the same race and Vaughan, relating to the famous singer/womanizer.