When I lay down on the floor and flatten my back, I can feel increased blood flow pulsating in my tailbone area. My penis returns to it's normal size at that time. It is not an erection. As soon as I get up, my penis shrinks abnormally to the size before I layed down. I am a hemophilliac, overweight and have broken my tailbone twice. Sometimes my penis retracts inside the skin folds. How can I get this to stop?