First of all, if you fail to find the funny in this post, and get offended instead, then you are a miserable, socially retarded troll who needs to get off the computer, leave your bedroom in your parents' house, and develop a sense of humor.
That said, I stumbled across this page and assumed it was a big joke. But apparently it's an actual yard game, rather than what you might suspect, which is a game for inbred, West Virginia hillbillies...or the Spears family. If you don't get it, well, I can't tell you what to do. Try moving along to the next post.
Every time I look at this T-shirt, I grin. I might even consider wearing one if it weren't so vulgar.