The first time I ever had sex during my period, I was drunk and I FORGOT. I was shocked and horrified when I saw the mess the next morning, but when my boyfriend at the time didn't seem to mind, I felt more at ease. I have heard that there are men who won't touch you during your time of the month, but I've never had a boyfriend who seemed to care in the slightest. It's not my favorite time to do it, because of the cleanup involved after, and also, I have less sensation down there during that time. However, the begging always ends up turning me on, and climaxes are a bit more intense than usually
If you stick to one position, and place a red towel underneath you, I find it minimizes the mess and distraction. Having wet wipes nearby make cleaning up easier. I wouldn't do this with someone new, but after you've been in a relationship for awhile and are comfortable with each other it's not really such a big deal.