He tries not to whimper when Spock ties his wrists together, though it takes special effort when he winds the rope around them so tightly. Not enough to cut off circulation even if he moves around, but definitely enough for him to feel the fibers dragging across his skin. Tugging and moving would definitely leave marks behind, which is something Jim immensely appreciates.

And he appreciates even more when he all but gets permission to do just that. Lips parted and dark gaze fixed on Spock's face, he tugs just once. The knots don't budge, the frame above the bed doesn't even creak. He yanks harder again, letting out a gasp that's more pleasure than frustration as the rope digs into his skin, a trace of pain that promises to leave marks behind.

The brief tightening around his neck makes heat spread all over his body, and he moves again. This time he tries to arch his whole body while tugging on the ropes, but he both knows and expects to not be able to go anywhere or do anything, not when Spock's sitting on top of him like that. The mere thought and subsequent realization that his expectations hold true make him let out a soft mewl. "Spock..."