He can feel Ianto shuddering beneath - around - him and somehow it makes an overwhelming wave of love wash through him. Yes, far more love than arousal, even though of course he is aroused, very aroused, but it's more about the trust and intimacy exquisitely conveyed here, the fact that Ianto let him do this to him, and is enjoying it as much as he is. He has to swallow and take a moment to catch his breath before he can do any more than grunt in response to Ianto's nod.
Then he smiles, and strokes his hands down Ianto's sides again to his hips, fingers curling round to give him a good grip as he breathlessly slides out and then pushes in again, gasping at the sensation and knowing it's got to be ten times more intense for Ianto.