Definitions by S.C.O.

Flip-flopping 

When two men are having sex, flip-flopping means to penetrate and to fuck each other’s anal one after the other. It often implies a longer sex; not to fuck and to reach to the ecstasy one by one, but to continue the cycle to stop fucking then to get fucked.

“Are you more top or bottom?”
“I like both. Flip-flopping is the best for me”

Flip-flopping by S.C.O. October 24, 2019