up their own ass
Being excessively proud of oneself. Basically when someone thinks their shit doesn't stink.
That Oprah woman is up their own ass.
Up your own ass
Constantly refers themself as being amazing at something
Keith, your're up your own ass all the time.
up my own ass
Robert
Robert who passes GCSE'S but can't get it right in real life.
up my own ass is something Robert would say, and that's gay
up my own ass is something Robert would say, and that's gay