I bought a butt plub, about 5 inches long, with a 4 inch by 4 Inch base, so it won't go up too far. When I am lying on my back, wiggling my weenie, and fondling my wife, my butt plug keeps slipping out, onto the sheets. How can I keep the Butt Plug from slipping out? Sitting up might be one answer, but I want to be able to stay on my back. Might be nice to have a specially designed bed with a butt plug cushion, adjustable for various positions. It might be nice to keep the Butt Plug inserted, when I am stroking on my knees and elbows, but I can't even keep it in when I am on my back. I am not really much of an expert, it seems. ..