Wiktionary
n. 1 The practice of using a bucket as a toilet, usually in prisons. 2 The act of emptying a bucket which has been employed as a toilet.
Wikipedia
Slopping out is the manual emptying of human waste when prison cells are unlocked in the morning. Inmates without a flush toilet in the cell have to use other means (formerly a chamber pot, then a bucket, now often a chemical toilet) while locked in during the night. The reason that some cells do not have toilets is that they date from the Victorian era and were therefore not designed with plumbing. As a result, there is no space in which to put a toilet, together with the expense and difficulty of installing the necessary pipes.
Usage examples of "slopping out".
I've had my moments, but mostly I muddle through by shoving a lot of energy into my spells until it doesn't matter if half of it is slopping out.
His body fats slopping out from under the sprung door, flowing like candle wax around the shoulders of a dead vampire thrall.
Bob had stood, his tail wagging, his tongue slopping out of his mouth.
In a small bar where you could cut the air with a knifea place that stank of marijuanaJake cornered the barkeep in a booth that he was slopping out and spoke to him.
And after all - and as you've often enough said yourself - do I really want to spend my life slopping out mental sewers?
Overall air of power and opulence, and not a whisper of cell fug and slopping out in the mornings.
Now it was all she could do to keep the water from slopping out of the pan that shook unaccountably in her hands.
Now, it was all she could do to keep the water from slopping out of the pan that shook unaccountably in her hands.