There was a retort in there, the Doctor knew it and held onto it, because this soft kiss was really worth not spoiling. He wrapped his free arm around Jack's waist, pulling him closer.

With with. It made the kiss feel that much more important, that much more serious. He couldn't rightly ruin an ordinary kiss, could he? But a with with kiss? Very easily. In fact, he could've printed something along the lines of "with with relationship destroyer" on it and it would've been accurate enough to pass the inspections of the Gratxian Entrepreneurial Laws.

So with this, he was careful, slow. Breaking the kiss only when he was absolutely certain it was the right moment to.

"Well, you've got reasonable taste in shoes."