I'm an expert
Formerly worldrevolution. The only reason I am nice to anyone else is to avoid being banned.
This is again one of those things that I wouldn't even second guess unless there was a GAF thread. Almost all the women I've been with want it even more during their period. Period sex is totally normal and enjoyable, especially for them. Not to say some women don't want/like it, that's normal as well. But for guys there isn't much difference.