I'm well happy with this 'zany' Japanese sticker.
Apparently it's a toilet humour funny, like the old "if you sprinkle when you tinkle...", meaning something like:
If you soil on the toilet, you should sweep it by yourself.
It's harder for a cleaner to sweep it later if you don't do.
This will take pride of place on my spare lavvy now.
Steve Rodgers, Sevenoaks/Fife