He is a bit sensitive there, though as worked up as he is he's pretty sensitive just about anywhere John might think of touching him. The muscles in Ianto's stomach jump at the brush of John's fingernails across his skin and he forces himself to roll his head down to look at the other man, catch a glimpse of him as he works him with mouth and hand. An action that almost proves to be his undoing right there and then.

He tightens his hand in John's hair, groaning and arching back into the press of his tongue. He can feel his breath catching in his chest, his body nearing that edge and he can't help a slight, involuntary jerk of his hips as he moves to try and pull the other man away.

"John," he all but begs, "if you don't--" If he doesn't want to finish this off with his mouth then he had better change his tactics sooner rather than later.