There are quite a lot of things Jack excels at in life, but as Ianto is concerned this particular skill is far more appreciated and important than things like shooting aliens or saving the world. He utters a breathless, "Oh, fuck!" as Jack descends on him, one hand clenching on his shoulder to steady himself. It feels completely fantastic and all he can do is tilt his head back against the wood of the door behind him, panting.
((I feel like Miracle Day might have provided something. I might make this my evening google project.))