Severus' nightmares are landscapes of blind pain, red with terror and blood-blue with the kind of cold that seizes at his bones, his throat, the soles of his feet. They are somewhat regular and he has learned to accept them, learned to lean into Draco's grip, constant and warm from sleep. Warm enough to burn against the cold. The real pleasure-pain of it is overwhelming and has become, slowly, reassuring.
Severus knows how to handle his own nightmares. He knows how to even his breathing out, how to bring Draco's fingers up to his lips where he can bite down, just a little bit, not enough to hurt, just enough to anchor himself. He knows how to whisper, "I'm here," so that Draco will be able to hear his appreciation aloud, as tangible as the silken, perfect skin of Draco's fingers.
He doesn't know how to deal with Draco's nightmares, the stiffening of his muscles, the way he will bite down on his lips, as terrified of his own cries as he is of Severus' touch, light and supportive.
Draco won't let Severus touch him in the aftermath, not at all, but Severus has figured out that he can use his magic to surround Draco. Whatever else Voldemort did with magic, he never used it to comfort Draco, that is something entirely new, something that even the echo of the dream can't confuse.
It is worse, Severus thinks--knows--to watch Draco struggle against his own panic, brighter and sharper, even, than Severus', undulled by years and repetition, than to travel through his own. Draco cries things out, mostly, mostly Severus related things, and Severus wants to curl his hands over Draco's wrists, to feel the strong-if-erratic pulse beat under his palm, to look into Draco's eyes and say, "I'm here," and mean it in a completely different way than when he is the one shaking, the one far, far away.
But in the morning, when Draco has reverted to his normal position of possession--at once sprawled over Severus and still somehow curled around him--when he wakens and blinks and there is nothing in his eyes but grey and perhaps a bit of weariness, then he says, "It's me."
Severus nods and pampers him in his own way--letting the water in the shower turn hot, too hot, the way Draco likes it. Letting the elves make too much food. Letting Draco read over his shoulder, which Severus finds to be completely obnoxious. Letting Draco talk about things that mean nothing, even when Severus really should be working, when Draco really should, for that matter. Things that Severus doesn't care about, society things, things that Draco knows and doesn't know, but that used to fit him like his own skin.
At night is when Severus will test out whether Draco can once again handle his touch, the skitter of his lips over a vertebrae, the brush of his bare shoulder against Draco's. At night is when Draco will melt into the touch, will drink it up, will act as though it might never again come. At night is when Draco will mutter, "sorrysorrysorry," as though there are things he should apologize for. Perhaps there are, but not to Severus.
At night is when Severus ignores the words as though they are nothing more than syllables of nonsensical sound and says, "I'm here."