Ianto returns the smile, taking a closer look around as Jack locks the door before returning that kiss. He's always loved the way Jack has of making sex fun and exciting no matter what they're up to and this is clearly no exception. The amount of effort he's put into it is genuinely touching as well and the smile only broadens at that question.
"I've been looking forward to it. And I must admit you've chosen a good spot for this; it's not as though we'll run short of supplies or ideas any time soon."