Ianto brought a hand up to touch the bite mark Jack had left, slightly disappointed as he felt it healing under his fingers. Then he moved his hand to take Jack's, linking their fingers again, not wanting the somewhat strange connection between them to end.
"Oh..." he said. He wasn't sure what he'd thought Jack meant. "So...heat...how does that work?" He didn't particularly like the idea that Jack might've reacted that way to anyone. He liked to think they were more than that. At least, he was reasonably sure that was how being in heat worked for animals...but it could be different for people from the fifty-first century.