A bunda is a term commonly used to describe a phat crummy arse.
Chad: Oi Timmy your wife has a mighty bunda you wouldnât mind if I filled her with my monster cock.
Timmy: no I wouldnât mind daddy
She had a rather crummy *bunda.
When the lads get together to bum it out behind the shed
Me: me and the lads are total bummer boys.