He's got a big turtle means he's got a big belly. It protrudes, forming a turtle shape. The shortened version is - he's got a big turt. It refers to men in the sense that it equates with a beer belly.
Hey did you see his turtle....it was even bigger than the other guys. Gosh, I hope you don't end up with a turt that big,
The art or act of taking someones backpack, taking all items out of the bag, turn the bag inside out, put all items back inside and finally zippering it back up.