Though it might be somewhat accurate in this case, Urban Dictionary isn't meant to be taken seriously. But then again, neither is banter, so I guess it's totally appropriate.
It's like Wikipedia without the quality control. For example, this can be found in Urban Dictionary. Pardon the language, but I think we're adults here:
Okay, bad example, admittedly, in that it's true, but you'd never find that in a real dictionary