you perform a flying squirrel by stretching out your scrotum upwards over your penis, and just let the head of your penis show. you pinch the bottom of the scrotum on either side with your thumbs and forefingers (carefully, please!) and pull it upwards. Your balls form the squirrel's back legs, and your pinched ends form the front legs. The membrane of your scrotum resembles the flaps of the majestic flying squirrel. The head of the penis is the head of the squirrel, of course.!
"The majestic flying squirrel is a glorius creature indeed, and quite a stunt to pull off, as it were."