The meaning is simple "fatass retarded-ass nerdy virgin" or "cum" and can also be "sup"
(option 1)
Random person : big blue tnt
Random person 2 : WHAT DID YOU JUST CALL ME?
(option 2)
The same person before : bro did I just drink big blue tnt?
The other person : Did you???
(Option 3)
Basically the person who says the examples : big blue tnt
The person who responds : sup