Firstly clear your head of any idea that chundering is associated with bunburying. I don't think the word chunder is on anyone's lips nowadays. It came to the fore with the appalling seventies Australian movie The Adventures of Barry McKenzie. It means, or meant, vomiting, especially after drinking too much. My favourite pseudonym for vomiting after drinking too much is riding the porcelain bus, that is when you hang over the toilet bowl while you throw up. I vaguely recall riding the porcelain bus once at least. The following morning, I wished I could just die.
Yet, in my school days, chunder meant something different. It was perhaps what is now known as a wedgie. An unofficial school sport was pulling up a fellow male student's underpants at either the front or the back to a point of extreme discomfort.
At the local Latrobe River freezing swimming hole where the water flowed down from snow capped Mount Baw Baw, this sport was modified to include bathers. But worse, coarse river sand was thrown into the swimming togs first and then you were chundered.
Straight boys can be very queer at times as AFL footballers often show us.