1. A hot girls ass.
It is used in situations when you are pointing out a nice ass, without letting the girl with the nice ass know what you're saying.
2. Any persons butt.
This one is used to talk about any person other than a hot girl but only to explain the action it is doing.
"Look at how nice that bedoo is."
"I hate that guy so much, I just wish I could bedoo doov him."
"If you don't stop doing that I will have to make you bedoo choog.