New fisting technique

Im always trying new techniques to stretch the slaves hole and make it cum even harder everytime. His hole is quite hungry and can handle some evere punishment. When double fisting I always lead with my right hand first followed by my left. I'll double punch fist him (which his hole loves). But when he's close to cumming and I want to apply more pressure inside his ass I expand my fists. My newest technique that has hime begging for it is I now switch my hands from right to left leading and it makes him cum instantly. We are now trying to get some depth out of that hole.