Immediately, his arm went around Sirius in turn. Alright, so what had happened wasn't outright rejection which was what he had been afraid of the most. But it also wasn't entirely an acceptance that this was a reality - that would have been too much to hope for, Teddy was sure. That hadn't stopped him from wanting it.
"I have... Pictures. Of the-of the four of you, you know. Back home. If this isn't a dream," and his mother, of course, but that wasn't part of the conversation yet. Right. Sitting down and starting with what had happened was a good idea and while he started towards a lovely looking sofa, he took a moment to face Sirius. Teddy whispered, "Will you please stay, cousin?"
He thought Sirius's presence would be a nice defuser for the both of them. But he had to pull himself away long enough to curl up in the corner of the sofa, making himself as physically small as he could without actually changing his size. That would have been too much. The Hufflepants were neatly draped across his lap like a blanket. "So... Time travel. Appearing at Hogwarts in the future," he almost added half-naked but then stopped himself, "And... Solid forms of family members past. Are you two certain this isn't a dream?"