noun phrase. Looking into the mirror is hard enough. Looking into the butt mirror is more than a mere mortal can take.
Real citation: "And I am resolved to NEVER turn my back to a digital camera. There are just some things that a woman should not view, one of which is her backside in snug jeans and a coat that is too short. I probably have PTBVSD (Post Traumatic Butt Viewing Stress Disorder - very unsafe). Maybe I should post it on the refrigerator. Of course, The Temperamental Mr. Bee may wonder why I refuse to go into the kitchen ever again. It would be hard to overeat if one could not bear to open the 'fridge ..."
(Jan. 2004, Bee-Mused, http://www.geocities.com/rblarchives/jan04bee.html)
Made-up citation: "Since losing 30 pounds this year, my case of post-traumatic butt-viewing stress disorder cleared right up. My bippy is a credit to America, unlike those traitors running against me."