Subsequent to this: today somebody got to the site by searching “what does one feel with insertions and fists?”.
Can’t help you, friend; it varies a lot depending on which supplements you use, what tier the Marines are at, what career paths people have chosen in character generation, which (if any) prewritten adventures you use, how seriously you and your Fisting partners take the whole thing, how well you know the other participants, how much you trust each other and feel safe in each others’ company, how relaxed you are and which and how much lubricant you use. There’s just too many variables!
Refereeing and Reflection 
Also depends on what setting the Pain Glove is on.
Making do without the glove is both heretical and unhygienic.