Drifting in attack tends to happen when attackers are too flat. Once they get the ball, the defence is already in a threatening position so they run sideways to avoid getting tackled. The other typical scenario involves the ball carrier who isn’t sure what to do or who (arrogantly?) wants to do it all his- / herself. The attacker goes looking for space, usually ignoring team mates outside. This has two effects:
1. The attacker eliminates at least one teammate as an attacking threat as he’s moved into his ‘lane’.
2. All attackers start to drift, so even if the ball is passed, there is less width than there previously was and the new ball carrier is doing the same as the person who passed the ball.
For defenders, this presents an easy side-on tackle or the opportunity to tackle / force a ball carrier into touch.
The simple solution in both scenarios is to pass the ball. The next attacker is likely deeper and should have more time to do something with the ball. An attacking player cutting back, looking for a switch might be able to pull off that play if the ball carrier is willing to pass. Cutting back might also fix or temporarily halt drifting defenders enough for the ball carrier or another potential receiver to find space.