The name given to a sneaker (usually a nike shox) during or after a shoejob if the guys cock is longer than the shoe, therefore making the shoe fit tight like a sock. A "filled shox sock" refers to the sneaker after the man cums in it, because a cock that large will most likely fill the shoe, and leave a yellow stain.
Shelly: So how was Alexis last night? Heard you got a shoejob.
James: Yeah, it was amazing! she gave me a hard jerk with her shox sock, and then i filled it to the top with hot cum.
Shelly: WOW! you must have a giant dick, Alexis wears size 9s. I'd love to have you squeeze into my shox sock sometime. Maybe ill leave my room open for a cum closet tomorrow.