A person who identifies themselves/or is identified as a T&S nerd, is someone who has an unhealthy obsession with the Canadian rock band called Tegan and Sara. They refuse to have an "obsession", and categorize it as an admiration or fascination.
They know every quote, have memorized every lyric, belong to .ca and teganandsarabanter.com, they have seen virtually every youtube video on tegan and sara, and have educated themselves to the point of knowing every story tegan or sara has ever told on stage or in an interview.
There are entire international communities of these people, and they are usually lesbians, as both tegan and sara gay. However, they refuse to admit that the reason they listen to T&S is because of their homosexuality. They will often wear tegan and sara merch, the newly released shoes, own pieces of emy storey's art, cut their hair like tegan and sara, or listen to other bands that are affiliated with T&S. These people are far more numerous than originally predicted.
Kate - Hey, did you see Kelly's new hair cut?
Anne - Yea, she is such a t&s nerd, she wears that jacket everyday too!