When you are nailing a seasoned veteran woman from behind, aka doggie style (look up if needed), and she is on all fours... in mid-thrust you grab or kick arms where her head falls to the ground and her forehead get a carpet or floor burn.
a new mexican road rash is the act of taking a giant steamy shit on a females face and then rubbing the shit in with a towel or a t-shirt creating the image of a road rash