The first rule is that it isn't Team Gai, not anymore. That name was shunned sometime during TenTen's death, in between one breath and the next, when her heart stopped and her chakra died and her soul left.
The second rule is that they don't talk to anyone not in the team that's no longer Team Gai. They don't have time for outsiders, for people that can't see, don't know, won't understand. Because now, not-Team Gai is no longer very understanding themselves.
The third (and final) rule is that they don't die. Ever. They drag their sorry asses back after every mission they're sent on, because they're better than anyone. They're better for her, because she was better for them, and they'll never let her down. Ever.
These rules are stuck in the back of Lee's head, right there with the rules about the Gates and protecting Precious People and other things he tries not to remember. But he remembers them anyways, and he follows the rules to a 't', because that's the kind of boy Lee is. Except he's not really a boy. He hasn't been a boy since TenTen's hand was cold in his, and Gai-sensei ripped it out of his grip, and he wanted to kill his sensei more than anyone else in the world. That was the day that Lee became a man.
Neji never did.
He's worse than Lee, Lee can feel it. Lee knows Gai-sensei can feel it too. Neji takes more missions than the rest of them, because Neji can't live in Konoha, where every where he turns around he sees girls who aren't there, tomboys that are dead dead dead, dead and gone, left to rot in the gold fields because there wasn't time.
Neji's a little crazy.
It doesn't bother Lee much, because Neji sees things Lee never has, and never will, and so Lee will make allowances, just for Neji. It's another rule, but this one is all Lee's, only his. It's 'watch Neji, because Neji can't watch himself.' Because Neji's too busy watching other things, like heart beats and poison in blood streams and the way chakra slips out, little by little, until TenTen?s dead and cold and pale all over again.
So when Neji comes to Lee, eyes narrowed and hands rough and ANBU uniform bloody, Lee follows Neji out the gates of Konoha to the fields where the grains are tall and gold and beautiful, in such an ugly way. And then Lee's quiet, just like they've all been quiet, ever since TenTen, and he lets Neji peel off his clothes, layer by layer, and lets Neji touch him with calloused fingertips, everywhere, and lets Neji look and look and look until the boy who will never be a man collapses from strain and too many missions and too little chakra and not enough will.
Then Lee pulls Neji close to him, lines Neji up so they're shoulder to shoulder, hip to hip, like comrades, and they lie in the field of wheat. He watches the wheat as it blows around them, hiding them from everyone and everything except the big wide blue sky, and he waits for a girl with kunai and hair ribbons to come fetch them home. But she never comes, and when Gai-sensei finally appears, late in the day when the sky's mostly dark and Neji's mostly cold and Lee;s mostly gone, Gai-sensei never says anything.
It's a rule.