When you do or say something that makes you seem retarded. From the Hallmark Hall of Fame movie of the same name starring Rosie O'Donnell in which she plays a "challenged" person who, surprisingly, rides the bus with her sister. What could have been a touching portrayal was ruined by the fact that she spent the majority of the movie screaming and acting like an insane monkey rather than a noble portrayal of a person with mental handicaps. So really, you are acting more like an insane monkey than a retarded person. Can be shortened to Riding the Bus.
"Do you really think you should wear leggings under your skirt? It's a little Riding the Bus with My Sister."

or

"Don't talk so loud in the movie theater. It makes you too Riding the Bus With My Sister."
by The Carester September 13, 2005
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