You get both, as a matter of fact, in the form of Peter/James.
Welcome to the Revolution
"Do you know," James asked Peter seemingly at random, "that our girlfriends have slept together?"
Peter took a good, long look at James, from the gel-spiked hair, to the tight Quidditch T-shirt, to the platform shoes which Sirius had Charmed to blink whenever James took a step.
"They'll be all the rage, you just wait!" Sirius had insisted.
"Really, have they?" Peter finally said, neutrally. "Not shocking, if you ask me."
"I feel sort of weird about it," James admitted. "You don't mind Skye fooling around on you, do you?"
"I fool around on her," Peter shrugged. "Why should what she does with other people have anything to do with what she does with me?"
"Mmm," James said vaguely, chewing on a glossed lip. "It's just…I feel like I ought to be jealous."
"But you aren't," Peter finished his sentence.
"Er, no," James sounded a bit perplexed. "I'm not."
"Welcome to the revolution, mate," Peter shrugged.
"Say, Pete," James eyed him thoughfully, "how'd you like to participate in a little experiment with me?"
"Yes," Peter agreed immediately, hardly believing his luck that the words 'experiment with me' had just dropped from James Potter's lips and he had been present, even if this wasn't going where he hoped it was.
James knocked Peter against the wall with the force of his advance, pressing him firmly into the stone with an open-mouthed kiss while confused hands skated down Peter's sides in search of something to hold on to, and finally settled on hips.
Peter grabbed the back of James' neck and urged him forward desperately. He was so caught up in exploring James' mouth, he didn't even notice James undoing his belt (clear with sparklies, nicked from Lily) until it and his jeans were unbuttoned.
"Gnuh?" he asked against James' lips. James flashed him a quick smile.
"In for a pence, in for a pound, eh?" he winked, then dropped to his knees.
"JIM!" Peter's jaw dropped. "You aren't really going to…EEP!"
Jim, whose mouth was full, did not reply.
"Unh…James, we're in the MIddle of the…huuh…hallWAY," Peter said frantically, "AnyboDY could see…ahhhh…us!"
James lifted his head for a second and Peter hissed at the cold air brushing him after the loss of James' mouth.
"Really, Pete," he said quickly, cheeks flushed, "are you the lookout or aren't you? Just keep an eye out!"
"Aaaungh," Peter responded weakly as James returned to his previous position.
Giving in to inevitability, Peter leaned his head back against the wall, closed his eyes (if any professors came around the corner, it was going to be far too late for his lookout abilities), and let nature take its course.
"Mm," James reported, climbing to his feet and kissing the corner of Peter's mouth. "Not half bad that. Say, this sexual revolution business does come with reciprocation clauses, right?"
"Tower," Peter managed to command in between gasps for air. "Tower. Right. Now."