A Stunt Double
When you buy a blow-up doll and name it after a real person, then you screw it and imagine it's the real person. You can even use it to tell the real person to go screw themselves.
I bought a blow-up doll and named it after my ex, then I had sex with it.
I got a blow-up doll and called it my crush, and I messed around with it.
I used my blow-up doll to tell my ex to go get a life.