When trying to figure out where you stand during a hand don't forget to take into consideration the strength of the hand you have represented througout. If you slow played TPTK until the turn, and they come out firing huge on fourth street, they probably think their second pair is good but your TPTK is still most likley best, because if it wasn't they would play their trips or whatever hand they have super super slow because you have yet to show any strength and they want to make some money.

If you raised pre-flop, then bet the flop, then fired again on the turn, and they come over the top you can probably safley lay down TPTK because you have shown strength througout and they are still coming over the top indicating that they are stonger via a re-raise.