The Brief: Dunk on is a term that means "to defeat" or "to take down."

DEEP DIVE
The term dunking comes from basketball and the idea of slam-dunking signifying a powerful display of athletic superiority. To dunk on someone is to one-up them in a way that shuts them up. It is similar to pwning someone, or a more aggressive way of throwing shade.
Charlie Kirk has officially set the Guinness World Record for most dunked on person in history.
— Thor Benson (@thor_benson) February 8, 2019
Seems like a good time to remind people of the time Delta dunked onAnn Coulter pic.twitter.com/gcXEfeIz4M
— jordan (@JordanUhl) February 7, 2019