Dr. Uzumaki figures out why Sasuke frequents his ER and is worried that Sasuke's inexperienced Dom will eventually cause permanent damage. To keep him safe, will he take over and find out why Sasuke isn't concerned with his life and why he keeps going past his limits? Can he show him the right way? A regression story of de-escalating from hard BDMS to soft kink. Naru/Sasu.