Ianto knew Jack meant what he told him, because he was right about the state of his resistance to do anything he didn't want to. Even Ianto had a task of convincing him at times, albeit with his own range of persuasive techniques that occasionally managed to turn things around to his advantage when Jack was feeling pliant enough. More than that, he trusted that Jack wouldn't play around with him like this, to take one of the only things that had always gotten through to him when sometimes nothing else did, and misuse it. Despite what started when between them, Jack was willing to let them try, fail or not, and he loved this daring captain all the more for it.
Without a beat of hesitation, his mouth opened to Jack's, and he was tasting him, his tongue tracing his lips before sliding home, caressing his tentatively at first, and then with greater ardour. He pushed himself against his lover, fingers gripping his hair hard. Letting his thighs press back against the desk's surface, fully aware that the furniture could take his full weight - Jack's too, for that matter - he put himself into a position that meant Jack was stood between his knees, his hips easily fitting into that triangle-space.
It was a small struggle to pull back slightly to look at him, still close enough that against his skin he could feel the feather-touch of the hair strands that fell over Jack's forehead. "Now it's my turn to be insulted," he finally answered in a breath, "that my two best qualities are overthinking and how to clean the dregs out the coffee machine." He raised a brow, as if to question where exactly in the list of his qualities such a kiss was placed. His eyes dipped to the tempting line of Jack's mouth once more, before he leaned in again, firmly. Jack had mentioned that practice made perfect.