A person at a school lunch table who is forced to take up the trash and trays of all others seated at said table. This person usually has low self esteem, is not wanted at that table, and/or is desperately trying to get in with a cool crowd. See also: trash bitch
It is ironic that the "cool" kids in my lunch have a tray bitch whose name is actually Tray! He takes all their trash up every single day and they still treat him like garbage.