On some of the ads I am seeing the term stupid booty.

What are they talking about ? Is that some time of marketing term to get one interested. I would say next after seeing that in an ad.

stupid booty refers to have a large buttocks.   stupid is often used to enhance a word positively.

Urban dictionary is great for these new terms

Here is another term someone told me today that means the same thing. "That ass in ignorant".

It means big, crazy, amazing, etc. For example... the car that just rolled by was "stupid"/ that car that just rolled by was amazing. It's like back it the day when "BAD" meant "GOOD" lol  =)