Odd question i know, but when does a turn in DM officially end? Does a turn in this game mean after one players attack phase, or does it mean after both players have gone?
Each player has a turn. After one player's Cleanup Step (which happens after the Attack Step), the turn ends and all effects end (other than "while active" effects).
There is no term yet in the game for a 2-turn sequence where both players have a chance being the Active Player.