"I know you're capable of it since regenerating, yeah, but no idea you could've back then, and I'm not sure what the metacrisis might've done with that, sooo... Even without remembering, you're both same-ol'-you and brand-new-you, so it's sort of a first time thing depending on how you look at it. Right?"
He's a little amused (in a very pleasant way) at their stack of hands, and he frees one up from the mix to hold the Doctor's in return, keeping the other on Ianto's. He looks at Rose with some consideration, then sticks out a foot as if to give her something to hold.