This refers to the phenomenon of the supremely annoying and sadistic older brother, after Wyatt's brother in the popular television program "Weird Science."
My brother was so totally a case of the Chet syndrome: he used to pull the heads off of my Barbies, take my panties to school to show his useless and creepy friends, "borrowed" my CDs forever, and hogged up the bathroom by showering until all the hot water is gone and I would have to shower cold. Brrrr!
This is a tree at which women in a group individually remove their bras, and leave them permanently hanging on the tree. This is usually part of a ceremony by a sorority or other group, and is usually attended only by women.
The Chili Dog Sisters had their annual bra tree ceremony, followed by a dinner at a Thai restaurant in Murfreesboro.