Can't Contain Me
Naruto and Sasuke never had sex lying down. When Sakura was around, sure, beds could be involved (or baths or benches or tables or anything really) but when it was just Naruto and Sasuke, lying down was never an option.
You don't lie down in the middle of a fight.
And that's what it was, really. A different kind of fight. It would start off as all their fights do: with a bit of posturing. I did this better than you. I could do this better than you. I am better than you. But now there was more of an edge to them.
They never used jutsu against each other. Not after last time. But all other bets were off.
Sometimes they'd be on a mission without Sakura, and tension would be high. They had someone tough to kill, or somewhere hard to find. Whatever. Adrenaline would be high, but it would have to be held in check for the sake of the mission. The calm before the storm, so to speak.
So they'd get snappy. Start bickering over stupid stuff. Start yelling over stupid stuff. Start punching over stupid stuff. Starting bleeding over stupid stuff. And then they'd start fucking over stupid stuff.
It was never pretty, and it was always noisy. They'd shout, they'd scream, they'd bite, they'd scratch; they'd do more damage to each other than the enemy usually ended up managing.
Naruto would go all red eyed and shove Sasuke up against a tree so hard he'd be pulling bits of bark out of his skin for days afterwards. He'd tear off his carefully-selected clothes with clawed hands, and fuck him until neither could move. Sasuke would buck and kick and rake his hands along Naruto's sides, before pleasure kicked in and he was mewling like a new born kitten.
Not that he ever admitted to this. And if Naruto ever brought it up, Sasuke was the one doing the shoving and fucking, with his own red eyes.
Sometimes Naruto turned into a girl, but that was only because it threw Sasuke off-guard. Sasuke was much more awkward around naked girls than naked boys. He'd glare at Naruto and tell him to knock it off, and Naruto wouldn't and he'd just keep pushing and pushing until Sasuke finally snapped and attacked him anyway.
But Naruto didn't do that too often. It only reminded them of how Sakura wasn't there.
Not that she minded. At all. In fact, some times she'd just sit back and watch them go at each other, watch them tear each other to shreds in the heat of the moment, her hand between her legs as they snarled and bit each other.
Until she moaned and drew their attention; and then she too was dragged into it by two eager males.
And then the fighting got really fierce.