It is only natural to take some time and consider all of the options If you have a big decision. However, if you deliberately waste time and think for extended periods in standard situations, you are considered to tank, and your opponents may call a “time bank” to force you to make your decision faster. Usually, the time bank will give you 60 seconds to decide, or your hand will be folded automatically.
Poker Tank Example:
If a player in an early position raises before the flop and you take two minutes to decide what to do from the small blind with a hand like 76o, you are tanking and wasting everyone's time since you will clearly fold.