An ass canvas is a toilet bowl. It can also be anything you decide to release the art of a bowel movement unto but primarily the bowl of a toilet.
Hey honey grab the camera! I just splattered the ass canvas with a real Jackson Pollock!
A dirt curtain is the (specifically long in length) ring of pubic hair surrounding the butthole.
Thanks Paul! I feel so much cleaner, your bidet really blasted my dirt curtain.
A smirk curtain is slang for a nice mustache. It is a curtain for the smirk.
Hey Dave did you just have a cappuccino? Youâve got some milk froth in your smirk curtain!