Straddle your guy during your next bedroom session and begin to pull off his shirt. As it reaches his wrists, stop pulling. Grab the shirt with one hand (grasp the part in the middle between his arms) and use it to pin his wrists back to the bed like makeshift handcuffs. The more confident you are about doing it, the better. You'll be in control, and he won't have a clue what hit him. But he'll like it.