Definition of peel a flop
When we say that we "peel a flop", we are calling a bet lightly. The phrase "peel a flop" indicates that the call is a "curious" call with a hand that is defending, but not exceptional. For example, if you have J7 in clubs on Q-8-9 with a queen in clubs and you call a bet, it will be possible for you to call the bet to "go to the next card". The player who "peels a flop" usually does so with the hope of hitting big on the turn or hitting a card that will give him equity on the turn.
Peel a flop, in position or out of position?
Peeling a flop when you have a specific plan in mind is not bad. But you have to have your reasons. Generally, when you peel the flop, it's better to be in position. If you are in position, you will be bluffed less often and it will be easier to bluff if you think it's the right play. Some players will peel a flop out of position, but it is probably always a losing play in the long run. If you're in position with a good plan in mind, it can be a good idea.