Its my pleasure to introduce you

Louis cannot help himself. He stretches a bit so he can whisper in Harry's ear, "That's what I'd do to you, when you're close to coming. Just think. You'll be so overwhelmed but you won't want it to end, not really, so I'll switch it to the seventh setting, give you just a few seconds to catch your breath but then it'll rock inside you, right against your spot, so hard you won't be able to breathe, but before you can finally come it'll stop again. How long do you think you could keep it there, just staying right on the edge?"

"I couldn't," Harry whispers, definitely shivering now. "I just couldn't tease myself like that, I'd have to touch my cock. If I wanted to... I'd need someone to do it for me."

Louis slips his hands from Harry's fingers to his wrist, where he clutches hard. "You would."

Or, the AU where Louis is the most helpful sex shop salesperson in the history of sex shops, and Harry really was just looking for a vibrator with simple instructions (yet ended up getting a hands-on demonstration).

⚠️not my story, from ao3⚠️ credit goes to the author LoadedGunn

https://archiveofourown.org/works/1124575?view_adult=true