A Celebration for someone that is getting ready to go to college has a trunk that they will take to college and they invite people to give them gifts to put in the trunk like; notebooks, bedding, coffee makers... All the essentials that a good student needs for college.
Woman allows herself to be stripped naked, get tied up, blindfolded, tossed in the trunk of a car and taken from party to exhibited and used sexually. She may or may not be completely drunk or high--by her choice. So far only known as a practice in the midwest.
"Mary Jane is getting crazy, I bet she'll want to go on a trunk party this weekend!