How do you teach receiving on the blind side?

I’d probably avoid the phrase “blind side” at first and coach what the player is trying to achieve. Ask: “Can you move somewhere the defender has to turn their head to see you and the ball?” A 3v3+2 possession game works well. Let one attacking player work between defenders and reward passes that find them where they can receive facing forward. The player will start noticing that standing directly in front of a defender makes the defender’s job easy. I’d also coach the timing. Moving behind the defender too early can simply allow them to adjust. At U12, the concept is absolutely useful. The language can stay very normal: get out of their eyeline, arrive as the ball can travel, and receive where your next action is possible.