An abbreviation meaning "Taking Our Sweet Ass Time" but said as a word. Even though it uses the word "our" it can still be applied to a singular person.
#1 Person A: What took you guys so long to get here?
Person B: We enjoyed the trip and didnt rush unlike you.
Person C: Yea we tosat'd it up here and had fun.
#2 Person A: Whats taking you so long Person B? You tosating it or what?