Tips on Safe Fisting?

Dear Rachel and Claire,

I've become really into fisting and now my girlfriend and I do it almost every time we have sex.  My question is one of safety.  We both like it when she goes in really deep.  It hurts (in a good way) but sometimes I feel strange twinges the next day.  Also, she's often pretty rough.  Again, I like it, and I'm not bleeding or anything, but I wanted to make sure I'm not risking damage to my internal organs or problems with incontinence or something.
-Fistee

A:

Dear Fistee,

If you follow the basic safety precautions, such as go slowly, use a barrier to block HIV transmission, have smooth fingernails, and don’t just pound away willy nilly, you should be fine. It sounds like you all might actually be pounding away pretty hard and frequently, and I’ve heard of people having urinary tract problems from that. You owe it yourself to have a chat with your doctor about this, just to make sure your twinges are just your muscles being a little sore. Also, check out our longer how to on Fisting.