How do you defend a team whose players constantly rotate positions?

I would move the defenders away from following one opponent and towards protecting shared spaces. The nearest player can pressure the ball. The players behind then ask who is entering the central space, who protects behind the pressure and whether a runner needs to be passed on. A useful cue is: if your player leaves, what threat enters your space? Use a 4v4 or 5v5 directional game and encourage the attacking players to rotate. The defending team scores a point for regaining possession or forcing play backwards while staying connected. Stop only when the same gap appears repeatedly. At U12, handovers need communication, but they do not require a complex system. The goal is for the players to see ball, space and teammates together. If they only see the opponent they started beside, a rotating team will move them wherever it wants. Use 4v4 to goals with one rotating neutral who joins the team in possession. The extra attacker creates regular movements between lines. Defenders score a point for forcing play backwards while staying connected. Only stop when two defenders follow the same movement or a central space is repeatedly left open.