Jack sucks in a long breath as Ianto finally climbs into bed with him, and then lets it out again as he cuddles up, pressing close as he possibly can and melting into the kiss. The shivers gradually die down and the intensity of his grip around Ianto slowly loosens, until the only things left are the kiss and their bodies pressed against each other. Eventually even the kiss has to end, and he snuggles in, ducking his head down to rest it on Ianto's shoulder in a reversal of their normal position.
"Wow." Happy shudder this time, and a brief tightening of his arms before they relax again.