The same thing as shampee and shampiddle; that is, a bottle of shampoo that's been wrecked because some dillhole uranated into it.
John Grass uranated into bottles of shampoo at the Juneau Receiving Home in the very early-1980s, thus converting them into shampotty and subsequently earning the nickname "The Shampoo Killer".
The act of farting in the shower. It is usually done without thinking first. For some reason only the gods know, these farts smell a billion times worse than normal gas passing.