The fear of wearing too tight of clothes, or over-constricting attire. This irrational fear could be due to a variety of reasons including the desire to conform to an urban dress code, or simply due to a low body image.
Jenny: Man, Richie sags his pants constantly! Look at how ghetto he is!
Billy: Yeah, man, he's totally got clothestrophobia. I have never seen him wear proper fitting jeans!