verb: to pelch means to take back a turn you made in a game after your turn has ended (especially after other players have also ended their turns)
Player 3: ...and I will move my piece here and take a victory point.
Pelcher: That's not fair! I didn't know you could do that. In that case I would have moved here instead.
Player 2: Hey, no pelching! You finished your turn and two others have played since then.
Pelching (or to pelch) is an unfortunate side affect of people who have failed to mature mentally. It is the act of trying to reverse actions taken in a game done by one who cannot fathom the concepts of losing or fair play.
Sylvia: Knight to queen's rook.
Andy: Hey, I didn't see that or I wouldn't have moved my pawn. Give me back by rook.
Sylvia: Hey, no pelching!