Tummy Musket
An erection, throbber, boner, or stiffy capable of tremendous expulsion power at any moment. The contents of said expulsion are difficult to aim.
"Damn man, I wasn't expecting Lady Gaga to turn me on, but when I saw her in a movie preview looking natural and pliant and as energetic as a jackrabbit in heat, my mind started to wander into fantasy. Next thing I knew I was warning my lady friend that I had a tummy musket. Sadly, that warning was too late. R.I.P."