Bum-bum

Kröner sat down heavily, staring at Petra's retreating bottom with its fluttering white bow as she finally continued her rounds, “Lovely bumbum, isn't it, Herr Standartenführer?” he said, addressing James.

Jonathan lies atop Mortimer, who falls backward to the floor. (Martha asks: "Did you hurt your bum-bum, dear?")

"Little Yan Er. It's no good sitting on a boney dragon. You will hurt your little flat bum bum!"