In the 60's and 70's the word "bitchin" was often combined with the word "ass", as in "bitchin-ass", used to describe the ultimate, supreme, primo, or a hot looking sexy girl.
> 1.Wow check out that bitchin-ass chick!
> 2.Man last night we smoked some bitchin-ass weed.
> 3.We had such a bithin-ass time at the concert.