it's not certain exactely what the T stands for but rather cautiously, I can belive T being the first letter of a word.
The most likely source, most expert say. can be tittle.
In my opinion can also be Total.
"I will quote this to a T."
"This is total BS! to a T!"
Queen Latifah is a BBW and probably a TOAT, but the fatty at Walmart in sweats and flip flops buying cigs, grape soda and circus peanuts is just a TOAT.