Lower the heart rate and lengthen the muscles. Pass gently to your partner, hold a light stretch between passes, and breathe slowly to finish the session calm and loose.
In pairs a few metres apart, roll a gentle pass to your partner then hold a light stretch (calf, quad, hamstring) before receiving the return. Keep the pace slow and the touch soft, and breathe steadily throughout. Rotate through the stretches over several passes to finish loose and calm.
Pairing players is the cheapest accountability mechanism a coach has, and it is the entire reason this format works better than telling a squad to go and stretch. A player stretching alone holds it for about four seconds, looks around, and stops. A player whose partner is waiting for the ball holds it until the sequence says otherwise, because somebody is watching who is not the coach.
That is worth taking as a design principle rather than a quirk of this exercise. Whenever an activity depends on players doing something unrewarding without supervision, giving them a partner converts an instruction into a small obligation, and obligations survive the coach walking off to collect cones.
The alternation is what gives each stretch its duration. Pass, hold a stretch while your partner has the ball, receive, pass again. Nobody has to time anything and nobody needs telling to keep going, because the rhythm of the exercise supplies the timing for free.
Keep the stretches light and static, held rather than bounced, and keep the passing gentle. A ball rolled along the floor is the right weight. If players are striking passes at each other then the heart rate is not coming down and this has become something else.
The honest caveat is the one that applies to every cool-down. Post-session stretching has a far thinner evidence base than its place in football culture suggests. Run this because it ends the session calmly and keeps the group together, not because it prevents anything in particular.
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.