I first heard this term used in Viet nam while going on a highland motorcyle tour between Da Lat and Hoi An. Apparently it is something you hope to aquire while riding. It is the alteration of your greenhorn rear into something more calloused and simian that will allow you to endure the long hours riding on the back of a motorcycle.
"The first two days are hell but on the third day you will have monkey bum and after that, no problem."
As it is day three now as i write and the said callouses have not developed, I have arrived at three alternative conclusions on the matter:
- Monkey bum takes longer than three days to develop.
- There are more factors involved than just the duration of ass slapping on a vinyl motorbike seat. Such as - ethnicity of the behind's owner, size of the rear itself, and number of time-outs during the ride.
- Monkey bum is not a numbed indifference at all, but does in fact describe something swollen, angry and red more appropriately adorning a baboon in heat.