You do it as a kid, then grow out of it, and finally its meaningful again. Break the pinky promise and i break the pinky. Its as easy as biting through a fucking carrot.
Of all the philosophers, sartre is the one youd expect to be into bdsm anyways.
(Yes foucault was def into it, marquis de sade too if you count him as a philosopher)
Now that I think about it i’m sure MANY were
Edit: just checked and yeeeep sartre wrote some stuff in being and nothingness. Also found like atleast 20 major philosophers who’ve atleast written about it.