A group of girls that contracted the same sexually transmitted disease from the same guy (in most cases the guy is a college baseball player).
Why do my pubes burn? Oh hell, I'm in Club Mydia!
I should have known it, Zach made me a member of Club Mydia last night.
Friend: Wow, that girl is the bees knees. I'm going to ask her out.
Zach: Dont do it! That ho is a card carrying member of Club Mydia!