Belmont Transfer
The Belmont Transfer is a sexual move named after the Belmont "L" train station on the north side of Chicago that has a free transfer between the Red and Brown lines. It is a metaphor for switching from vaginal sex to anal sex, also known as "switching from the Red line to the Brown line."
Matt: "I took home some random girl from the bar last night"

Sean: "Nice! Did you pull the Belmont Transfer?"

Matt: "Damn straight kid!"