A woman with small boobs buys an old mirror from an antique shop, and hangs it on her bathroom door.
The next morning, she playfully says, "Mirror, mirror on my door, make my boobs size 44!"
There in a flash of light, her boobs grow to enormous proportions. She immediatly runs down to her husband, and tells him the startling news.
The both go upstairs to the bathroom, and the husband crosses his fingers, and says, "Mirror, mirror on my door, make my penis touch the floor!"
There's a flash of light, and both his legs fall off!