Just... Graves needing several hours of alone time with more than his hand, ok. And, because he's a wizard, he has access to things like nipple clamps that pinch AND suck, collars that choke but never strangle, and self-fucking dildos that taper off and plug him the second it feels like he's going to come too soon.

BONUS: Credence or Newt as accidental voyeurs. (They didn't mean to perv on Percy but he was moaning their name loudly and desperately enough for it to require further investigation)