Percival hates being tickled. He hates it.
Even when he was young he hated it, particularly the way his older brothers used it against him. The first hex he ever cast was to make them stop it. Now, any lover who tries it better knock it off quick if they want to remain in his bed.
It’s not that it’s silly or undignified – he can live with embarrassment. It’s the way it feels on his skin, how it makes his muscles twitch and jump with a horrible invasive crawling sensation. The way people seek out the most sensitive places on his body and think it’s okay because “it’s just tickling,” when they otherwise wouldn’t dream of touching him that way. Most of all he hates that it makes him laugh, because it isn’t funny. It feels awful, he doesn’t like it, and when he’s laughing no one believes it when he says “no.” He decided a long while ago that tickling was invented to torture him, specifically and personally.
Gellert Grindelwald agrees.
He discovered it by accident. It wasn’t the first thing that came to mind when thinking of ways to tame and punish his pet without risking permanent damage, but when his fingers tease over Percival’s naked side it’s impossible to miss the way his jaw tightens. Gellert is so curious what caused that reaction. He digs his fingers into Percival’s side viciously, and Percival jerks away but there’s nowhere to go. He’s relentless, and when a laugh claws its way out if Percival’s throat it only takes one look at his stricken expression for Gellert to know he’s won.
“You like that.” Percival shakes his head and struggles violently, but he can’t make himself stop laughing. And, oh – he’s even getting hard, the slut. “l can see you do. Don’t worry darling, I’ll give it to you. Your body wants it.”
Gellert tickles Percival until he cries, and then leaves him hanging limp from his restraints while he ponders the best way to make use of this information.