So, what if Harry doesn't?
He was told again and again by the Dursley's about how unclean and perverted it was after his class did a sex education session and Aunt Petunia found out.
Aunt Petunia's words were hissing, disgusted, as she accused him of things he didn't understand. Uncle Vernon's words were booming and angry, accompanied by smacks to make sure he got the message into his stupid head.
He was punished when his sheets got wet in the night a year or so later. Even though he didn't mean it and was frantically trying to wash them himself when she caught him.
After that he waited until Aunt Petunia was out shopping to wash away his shame. At least when it started to happen at Hogwarts too, the elves didn't spit on him as filthy and wrong, even if he felt like it.
All the boys in his dorm did it. They were older when they started to do it. Younger when they talked about it. Harry could hear them in the night sometimes, before he learned to cast silencing charms.
He tried it once, that summer of second or third year. He couldn't do magic at Privet Drive and his surprised oh as it happened was loud enough for Aunt Petunia to hear as she made her way to the kitchen for a late night tea.
What happened next woke the whole house as he was dragged kicking from his bed, Uncle Vernon's roar of disgust in his ear and belt on his arse.
He didn't try it again.
Later, he kissed girls. Cho. Ginny.
He still didn't do that.
He thought maybe he was a freak after all, like Aunt Petunia had always said.
In seventh year he couldn't think about sex. Everything was panic, escape, misery. He would never have done it with Hermione in the tent anyway. He couldn't - no matter how much Ron and the others talked about it like it was normal - he couldn't do something so disgusting with her right there.
Later, he came back for an eighth year. A chance to finish what he'd started so many years before. He was roomed with Malfoy, but Malfoy was different now, quieter, still sharp but less cutting. Harry felt Malfoy's eyes on him often, but the looks weren't accompanied by the savage words he was used to, and whenever he looked back, Malfoy avoided his gaze, so Harry left it alone.
Sometimes he watched Malfoy too. He wasn't really sure why.
It was months before Harry realised that Malfoy was only quieter during the day. The silencing charm on those around him had become second nature after so many years (never on himself. He couldn't bear the thought of not hearing what was coming from him).
He'd fallen straight into bed that night, fully clothed after a grueling Quidditch training, pushing himself harder than he should have, but relishing the adrenaline and the chance to feel alive.
It was late when he was woken by the sound, pulled from sleep by the breathy whisper in the darkness. He lay in bed, eyes closed as he tried to pinpoint the noise.
'Fuck, oh fuck. That's it. Right - oh - right there-'
It was Malfoy, he realised, his eyes opening with a silent gasp. Malfoy was - was pleasuring himself.
The light from the moon spilled into the room illuminating Malfoy's bed. His hangings were open and his body was long and pale in the moonlight. Harry's eyes moved down Malfoy's naked chest, the buttons of his silk pyjama top open, leaving it hanging half off him.
His eyes travelled lower, even as he told himself this was wrong. He shouldn't be watching it. Malfoy - Malfoy could do it, but Harry shouldn't watch, shouldn't even think about it. That was Aunt Petunia's voice in his head, he knew, even after so many attempts to banish her.
Malfoy's pyjama bottoms were pushed down to his thighs. His cock was wet, shining in the light as he slipped his fist up and down it. Harry watched as his hips shifted with the movements, jerking up in a way that looked almost involuntary.
'So good,' Malfoy whispered in the darkness.
Harry's gaze jerked up to Malfoy's face but his eyes were closed and the look on his face was on of blissed out pleasure as he continued to whisper to himself, the soft, wet sounds of his movements carrying in a way that made the divide between their beds seem far smaller than it was.
'So good,' Malfoy said again. His movements began to speed up and he moaned softly. Harry watched his face, something stirring inside his chest, an unfamiliar heat curling within him as he realised Malfoy was bringing himself off.
'Ah, fuck. I'm close. Potter. Fuck. Harry.'
Harry jerked back, bedsheets rustling and a sound of shock escaping him as he registered the words Malfoy had just said. Malfoy was doing that and thinking about him.
Malfoy's eyes flew open at the sound and he looked across the room into Harry's bed, his movements stilling, though he made no move to cover himself.
Harry froze, unsure what he should do. Turn away? Leave? He couldn't bring himself to look away from Malfoy's eyes, shining in the dark.
Malfoy licked his lips and Harry's eyes dropped to them for a second.
'You forgot your silencing charm?' Malfoy said, his voice a murmur in the night, his hand still on his cock.
Harry nodded, unable to make himself speak.
Malfoy watched him a moment longer and then slid his hand up his cock, rubbing his thumb over the head, a soft breath of sound escaping him as he did.
Harry's eyes dropped to the movement and he felt that same curl of heat in his chest, spreading through his belly.
'I could stop?' Malfoy offered quietly.
Harry felt a hundred thoughts rush through him. Shame, guilt, punishment... desire.
He shook his head, slowly, eyes meeting Malfoy's again.
'No,' he said, his voice a cracked whisper as it travelled the distance between them. 'No. You don't have to stop.'
Harry thought maybe he would never do it. But this, watching Malfoy in the moonlight as he stroked a hand over himself, eyes fierce through the darkness, body tight with tension...
This was beautiful.
Harry thought this, maybe, was something he could let himself have.