This porn video tag is a combination of elements related to the popular anime series, Avatar: The Last Airbender. The term "Avatar" refers to the title of the show, while "Aang" represents one of the main characters in it. The term "hentai" is a Japanese word which literally means "perverse" or "perverted", and in an English-speaking context, it typically refers to anime or manga that features explicit adult content.
So, this tag refers to pornographic content featuring the character Aang from Avatar: The Last Airbender in a sexualized manner, often depicted in an anime or manga style. This material is intended for adult audiences who enjoy this particular combination of elements.