Taking the limp penis and pushing in back into you as far as it can go. Then you take the loose scrotum (best when out of a hot-tub or hot shower) and fold it from under, on to the top of your penis therefore resembling a turtle hiding in its shell.
when you are taking a poop in a public place and someone walks in and you dont want them to hear you in the stall taking a loud poop so you clinch your butt to be quiet