A lewd but ambiguous sexual act. It's implied that cornwalling is something done in places with populations of less than 5 000 and more farm animals than people.
You remember that countrychick we met at the bar last night? I ended up cornwalling her in a barn with her cousin Earl!
A act when somemone is fucking some one o something in the ass.
Steve: John what did you do last night.
John: I went cornholling with your mom.
Steve: What the fuck John I thought we were freinds?
John: It's not my fault your mom is a anal sex freak.
Steve: Fuck you