Similar to the grenade, a rusty refers to a unsightly female. Cutting a rusty refers to hooking up/ skeeting with an aforementioned rusty. Guys who cut a rusty will not be praised for their accomplishments but instead be chastised for at least one week. If you contract a disease, such as the clap, by cutting a rusty you will be forever labeled as rusted.
Andrew: Dude, I think i heard you Cutting a Rusty last night. Shit was gross.
Cole: Dude, we need to go to the clinic, i think I'm rusted.