Possible R1 timeline; could be taken as vague LelouchSuzaku but also not.
When they were just kids, they formed a system of communication that only they could understand.
A tug on the collar, a touch to the elbow, the pulling of a shirt hem all having different meanings, some unique significance that made it special, somehow grown up.
And then they grew up.
Lelouch was nearly certain that Suzaku would have forgotten; he'd already had to simplify the code so that so that the younger boy could have been capable of memorizing it in the first place. But he remembered, he always seemed to remember the most trivial of things, the more important ones seemingly glossed over.
And maybe it had always, always, been like that; Lelouch thinking he would have forgotten, should have forgotten, that it never really mattered in the first place. And at times he thought, for just a fleeting second, that when he was gone, cold and dead and hardly a thing to be remembered, Suzaku would never forget.