Just another one of those words that you don't hear correctly as a child, and then continue to mispronounce throughout your childhood and early twenties.
See 'mechanical veins'
"John, put the bottle down! That's enough chukney on your potatoes!"
A water-based poo that can come out of your bottom.
Gay 1: Ah, thats better.
Gay 2: You better of got rid of your bum chukney, for tonight. ;)