Jack'd get a lot of that hitch, purring encouragement directly into his ear and gasping out swears as quietly as he could. There were others in the museum, after all.
Later, when they were both as sated as they could be, Ianto's voice'd still be gravelly and his accent thicker, but there wouldn't be any of the urgency that there had been. "Gotta find lube," he murmured, passing a hand (the clean one) through Jack's hair affectionately. "Thank you."