An Alabama custard musket is the act of having anal sex with your sister, cousin, aunt, or mother, and ejaculating into their rectum. Once this has been achieved, lay on your back, with the female participant squatting over you. She then farts out her man-custard frosted stink nuggets at you at alarmingly high velocity while screaming "the South shall rise again!" as you try to dodge the hailstorm of custard frosted butt bullets.
Oh dang man, my cousin Bobby-Jean Billy Joe Bob Possum Dog gave me the worst Alabama Custard Musket. It was so bad even Mountain Dew wouldn't wash it out of my mullet.