The Master absently squeezed the Doctor's hand. He wanted to push, to get Jack to tell him what had triggered the reaction earlier, but... He sighed, wrapping his arm firmly around Jack. "Fine," he grumbled, trying to turn his attention back to the interplay between Jack and the Doctor. Not commanding, or controlling at the moment, because he didn't want to find out that he'd caused that reaction. At all.
Jack waited a beat before turning his attention back to the Doctor. Pushed the shirt aside, leaning forward to press a kiss to the dip where the collarbone came together. Pushed gently with a hand on his shoulder, wanting him on his back.