The act of leaving
a) an elegantly large
b) a violently sprayful mess
in the tiolet bowl for someone else to discover.
Noun form: turdvertisement
I turdvertised a real long earth-snake at the bus station the other day -- man was I shit-proud!!!
After eating their chili with beans last night, I went back and left a horrendous turdvertisement in the restaurant's bathroom.