Never slow play that situation, unless you are trying to give the impression you are also semi bluffing and chasing the flush. Also, top pair is only one pair, trips, two pair, and certain pockets still defeat you. If I were in that situation, I would give a testing bet to see if they are still in, this bet should be relatively high, but not too much of a percentage of your stack (due to the fact you do not have the best hand in that situation.) If they initially bet, then raise and if they re-raise, I would fold. If you initially bet and they raised I would more than likely fold or make an uneasy call. But more than likely they will bite the bullet and either call or fold then. If they do you know your hand is dominant and hope they miss on the turn.