This video talks about an Erne, when to look for it and when to take the opportunity to take the extra steps and be aggressive.
You should keep a close eye on your opponent’s footwork. As soon as you see their shoulder turn to go back to the sideline, that is when you know that the only shot that they have with their paddle at their angle is about a 2-and-a-1/2-foot section on that side of the net. So you’re looking for their shoulder to turn as you get closer to that line.
Let’s say your opponent turns and the ball doesn’t come to you as you’re attempting an Erne. That’s fine. Your partner should be able to balance the court, see their shoulder turn, and recognize that there’s no way that they’re able to hit that ball for a cross-court shot. This means that your teammate needs to come over and balance the court in the mid-center court when they see you going for that Erne.