A phrase used to describe someone with an adrogynous appearance, like Hilary Swank in the movie Boys Don't Cry. This is a slightly inappropriate comment because the movie is based on a real person and the storyline is sad BUT most people don't read that much into it and just get the point that Hilary Swank is unattractive as both male and female.
"OMG! Did you see what Leslie is wearing today? Totally Hilary Swankin it!"
"Man, I dunno what's up with Josh but he's been Hilary Swankin it ever since he watched that one episode of Oprah!"