This word was once used to describe flatulating while kissing a beloved and was considered the deepest sign of comfort and offection towards the receiver of the odorus kiss.
Today, this word is modernly used to describe flatulence that puckers the anus. In rectal punctuation, it is known as an exclamation point "!"
"Did you hear that fartkus?? Your butt just said, 'ooooooh, snap!'"