Slow playing is a strategy when you check or call a bet with a very strong hand in a hope that someone else playing will raise. The goal is to make your opponent think that you have a weaker hand when you actually have a very strong hand, eventually inducing them to continue betting and inflating the pot. You ramblingly give your opponents a chance to improve their hands when you slow play.
This situation ascends when you have a tight player behind you and you are on the flop. Let’s say you are holding a pair of 8 and the flop is A, 8, 5. Here you can slow play in the hope that the tight player behind you has an A and will certainly bet it. You don’t have to raise until the river if the tight player is betting. Let’ say if the flop is 7, 8, 9 and no matter how awesome you slow play, but it won’t convince a tight player behind you to take a shot at the pot. You will probably be beaten by a straight if the player bets else the player will check on you. So, here it doesn’t make much sense to slow play.
If you have the best hand and there is a bet to you, then it is obvious that you will call the bet to hide your strength and let the opponent (bluffer in front of you) make the next move. The move is a bit obvious as you can simply call again if the player bets again on the turn. The best thing you can do in this situation is to look weak and take a long time to make your call.
Slow play is certainly profitable on the flop if your opponent (bluffer behind you) is a kind of player who bets at every pot. The secret would be to determine what he will do at the turn, you can call the bet on the turn and check on the turn if you know he will try his luck at the pot again. If you are not sure about his, then it is really essential that you take control of the betting.
It is indeed a sober way to disguise the strength of your hand and put many extra bets into the pot. However, you should only slow play when you have a very strong hand. Many weak players slow play way too much, but this is one of the reasons which make your bluffs very easy to pick off.