A Picnic Table Shirt are shirts worn by guys at many bars & clubs around the world. The reason they are called Picnic Table Shirts is because they look very similar to how a picnic table cloth looks. Anything Plaid or Flannel qualifies as a picnic table shirt. They come in short sleeve and long sleeve button downs. Try to avoid this awful current trend.
These Guys often wear very tight skinny jeans that are tighter then anything your girlfriend would wear.
When at a club or bar hanging out with friends you will notice a group of guys wearing the same kind of shirts similar to the kind of shirts you would see on a picnic table cloth.
One of your friends will go is that Paul Bunyan? Your next friend will go I don't think they are lumberjacks. Then you'll reply that they are wearing a picnic table shirt.