1. An informal term for the buttocks.
2. Bum-bum hole can also be a term for the anus
1. While riding on the Amtrak keystone train to nyc on the metroliner cab car ( or amfleet cab car) #9645. I saw this lady with a crop top and a very tight pum pum shorts and with a huge, sexy and firm buttocks, many guys onboard the train & the conductor was flirting around her, and I was about to slap that sexy bum-bum but she had a guy (an ugly guy) sitting next to her so I didn’t :(
2. Ugh, I have sand inside of my bum-bum hole from the beach