Keep the ball when somebody is on your back. Take the first touch across the body rather than into the defender, get side on and low with an arm across for distance, protect it while you work out which side he is on, then turn out away from him and come away facing forward.
Mark a receiving zone roughly 22x18m with a gate of two cones at the far end. A server starts with the ball, a receiver waits in the zone, and a defender starts tight behind the receiver. The server plays it into feet. The receiver may not pass it back: he has to keep it, shield it, and eventually turn out and carry it through the gate. Start with the defender applying light pressure and no tackling, only pressure and contact, then let him tackle once the body position is holding up. Rotate all three roles every two repetitions and work both sides so players learn to turn away from either shoulder.
Listen to a touchline on a Sunday morning and you will hear one instruction above all others: pass it. It is well meant, and it quietly teaches players that the right response to pressure is to get rid of the ball.
The governing-body guidance for this age group is unusually direct about the cost of that. Coaches are warned against telling young players to always pass early to the easiest option, because staying on the ball is itself a skill, and a player who has never been allowed to hold it under pressure has no answer when there is nobody to pass to.
Shielding is what makes staying on the ball possible, and it is listed alongside dribbling, receiving and turning as a component of mastering the ball rather than as some specialist forward's trick.
The body position does nearly all the work. Square to the defender, the ball sits between the two players and belongs to whoever is stronger. Side on, with a wide base and knees bent, the player's own body is between the defender and the ball, and strength stops being the deciding factor.
The arm across is worth teaching properly rather than leaving to instinct. It is not a push, it is a distance sensor: it tells the player exactly where the defender is without needing to look, and it keeps him an arm's length from the ball.
Which foot the ball sits on decides everything else. On the far foot it is unreachable. On the near foot the shielding is decorative, because the defender can simply poke it away past the player's own standing leg.
Then the turn, which is the part that separates shielding from hiding. Holding the ball indefinitely achieves nothing on its own. The player should be feeling which way the defender is leaning through that arm, and then spinning out the other way, coming away with the ball and facing forward.
Expect it to look ugly for weeks. That is what learning to keep the ball looks like, and the alternative is a player who passes back to the keeper every time somebody breathes on him.
Save it to your private drills, then change the animation, adjust positions, swap equipment, or drop it into a session block. Or start from a blank pitch and build your own.