LIke puttng 'anything' large ( a fist is pretty large) into your vagina, depending on how it (fist, large dildo, etc)is used etc. I would imagine potential risks may be involved. The ability to tolerate 'fisting' speaks for the size of your vagina... is that a problem from 'normal digital or penil playfulness? with loss of sensation? I guess I'm curious about your comfort level with 'fisting' in general.