The undercover city is what you call a stain usually made by the sexual reproductive byproduct called sperm is wiped on a mattress when done masturbating. This will most likely be hidden under a sheet cover or pillow.
Jimmy: Ew, what the hell is that on your mattress.
John: Oh that, it's my undercover city.
Jimmy: Why...?
John: I have a problem, huh? :(
Jimmy: Yeah. You do.
John: Oh that, it's my undercover city.
Jimmy: Why...?
John: I have a problem, huh? :(
Jimmy: Yeah. You do.
by Babyfucker69420 August 19, 2021
Get the Undercover Citymug. by TOW DOWN!!!!!!!!!!!!! June 22, 2023
Get the lego city undercovermug.