Really, even if you didn't know about the backstory, it was quite funny. If you did, though, it was down-right hilarious.
Team Seven never applied for a name-change. Actually, they were quite vehemently opposed to the idea, really. Because sure, Seven was just a number, and it was meant for a genin team, and they needed it back, because the fact there was always a team seven missing from the year groups was annoying, and so on and so forth, for a thousand mundane reasons that made perfect sense until you remembered that Team Seven was Naruto and Sakura and Sasuke. And Sai and Kakashi and sometimes Yamato too, but mostly just the trio. And Naruto was foolishly sentimental, and Sasuke was just possessive, and Sakura had a hard enough job getting them to do more important things, she wasn't going to argue about a name.
Still, they do say if a ninja gains a name it means they're important. The Yellow Flash. The Sannin.
Kamaitachi was definitely not what they had in mind though.
I mean, technically they weren't. But technically the Sannin weren't Sannin either, just crazy jounin who had special clearance. And it wasn't as if they could chase every enemy down and tell them pick a different fucking name, because itachi makes Sasuke even more of a bastard, and the fact it's a youkai makes Kyuubi pissy, and the fact that it's supposed to be three brothers gets on sakura's feminist streak. They try for a bit though, but eventually 'Kamaitachi' is a common moniker.
It is, inevitably, Naruto who brings it up first.
Admittedly it was bound to come up, but Sakura thinks perhaps that in the middle of that post-sex haze (she knows the medical term is post-coital, and that it's called afterglow and she can replicate the effects or subdue them with a few choice micromedical jutsu, but damnit this is her fucking sex, it's been the first time in a week and medical jargon can bloody stay out of it) where Sasuke finally cuddles and Sakura feels like a delightful pile of jelly, is a bad time.
"Kamaitachi were supposed to be brothers, yeah?"
They would warn him off with a growl or something, but they feel far, far too much like comfortable squishy jelly.
"So does that make us incestuous?"
And suddenly Naruto finds himself on the cold floor outside of the bedroom, two furious sulking lovers in bed WITHOUT HIM, and still he grins.
He's getting them over the brother issues. Slowly. Because he might be on the cold floor outside the bedroom, but there's no kunai or bruises, and there's a suspiciously sex-smelling blanket.
That, and he knows they've both approved the name-change that he left on the drawer, and which he's going to post in the morning.
For something that wasn't their choice….it's a pretty cool name actually.
But he swears, the next time Konohamaru greets them as the three musketeers, he's going to pull the knocking down, Sasuke can cut him up, and Sakura can heal him so it still hurts, and he'll be able to deal with Kamaitachi because in a way it's true.