In S/M, particularly in the male gay community, the
practice of fisting, with something more: the fister
holds a little ball in the fisting hand, making the hand
bigger and the experience, I am sure, much stronger.

In BDSM (especially gay BDSM), this is considered to be another word for 'fisting'; the reason for this name is because the word 'fisting' conjures up imagery of violence and pain, whereas when done properly, it is one of the most powerful, pleasurable, and relaxing experiences that one could ever hope to feel.