Also called Bonerface
Used to denote a girl who is so beautiful and has such a perfect figure that just looking at her is enough to give any straight guy a massive erection or boner.
Dude1: hey check out that girl!
Dude2: Man! She's beautiful and has such a great figure!
Dude1 & Dude2 (with their hands on their respective crotches): She's an eriface!