Puss In Boots
"I'm so tired," Tom said suddenly, in a little boy voice, "why am I so tired?", and his eyes rolled back into his head and he passed out. And the first thing Grindelwald thought was, fuck this. Tom was supposed to be his apprentice, not the other way around. What kind of Dark Lord were you when you had to carry your servants home and put them to bed? But at the same time, looking at Tom sprawled in the grass, Grindelwald was reminded of how young he really was, how powerful. How hard he'd worked at his lessons. So he levitated Tom and guided his body back into the secret headquarters and let him fall on the bed and not on his pallet by the fire.
Naturally he couldn't let Tom sleep in his bed, not fully dressed, and Stripping Spells were often unreliable. Grindelwald unbuttoned the boy's shirt, rubbing gnarled fingers over the boy's lovely pale English body, almost by accident. He was drawing off Tom's trousers when the boy woke and smiled up at him with the satisfied smile of a pampered pet. Grindelwald was momentarily uneasy, and yet, surely this was a coincidence. Surely Tom hadn't meant for this to happen? Oddly, Tom didn't seem to be wearing any drawers.
It had been a long time since Grindelwald had seen so much hard young flesh--nearly three centuries--and he rather forgot himself. Tom didn't seem to mind. He arched his back and leaned into Grindelwald's touch, and he tangled a hand in Grindelwald's hair and drew him down for a kiss. And he kissed like a siren and not like an English orphan boy at all, at least not the way Grindelwald remembered English orphan boys, and he had known Dickens's Oliver quite well.
In fact, soon it was Grindelwald who was flat on his back; with Tom's mouth zeroing in on his wand, and Grindelwald could not quite remember why he'd stopped taking apprentices. Tom was such a clever little--unique application of the Stiffening Spell, and was it possible he'd made Tom beg for the job? He hadn't felt so excited since the Industrial Revolution. Tom's mouth is very warm and wet, exactly the way he likes this sort of thing, and Tom knows all about slits and holes and he has a tongue like a snake. Grindelwald knows he's found his heir apparent.