The entire contents of this one so far:
Prompt: Give me John ‘3 Continents’ Watson, formerly renowned ladies man with unparalleled sex skills having his first time bottoming to Sherlock. Make it nice and slow with Sherlock smoothing over first time anal anxieties and John finding out he loves taking cock. Bonus for aftercare and Sherlock banging on about John’s virgin arse and all the filthy things he’s planning for it.
***
John feels horribly exposed, more like a man about to have an exam than sex. It’s not like he doesn’t know about anal sex; he’s a doctor, he’s had gay patients, he’s had talks. He had a girlfriend once who’d tried pegging her ex, but it hadn’t gone well and she’d never tried it again, and it had been more in the vein of ‘crazy things we have done’ than a suggestion. He’d just never thought it would apply to him.
“Guess I’ll have to give up the ‘ladies’ man’ moniker,” John jokes weakly.