Arse sludge
A particularly runny expultion of arse waste that, although not quite runny enough to be full blown shit juice, has a sludge-like texture, possibly due to a curry eaten the night before washed down with some beers.
"Mate, expelled some rancid arse sludge this morning after that madras last night, i took a sample in a bag if u wanna compare it with yours, we can make it into an arse sludge competition..."