"Yeah, I've got girl stuff going on. Anyway..."
"Girl Stuff? As in, you're on your period? The cramps are ruining your day? Etc.?"
"Um...yeah." She gives me a look like I've just grown a second head. "It's..."
"Yeah, that sucks..."
I am so used to (in my mind, unfortunately) blowing the minds of various women due to the fact that I have no problem talking about periods, feminine products, etc. I personally find that attitude that it's all icky and strange, and should not be talked about, rather barbaric, and belonging with those people who teach that genitals are things of the devil, and the like.
It's a normal, monthly thing that happens with all women between the onset of puberty and the occurence of menopause. If you're unwilling to talk about that much of your girlfriend/friend/significant other's life... then don't bother getting frustrated the next time that individual doesn't want anything to do with football, or discussions on the art of farting, etc.