The act of regurgitating on ones penis for the purpose of lube, in leu of KY jelly (or other various lubes). First tried in Portland, OR; and the stomach acid burns the receiver's vaginal or anal areas making them blurt a ghastly howl.
Ben: "Dude, I was in a pinch so I pulled a Portland Howler."
Henry: "Did it hurt?"
Ben: "It tingled a little bit, but she was howlin'!"