Retain possession from a throw-in and progress the play. Throw short and firm, receive and lay it back first time, and use the free thrower to switch the ball inside away from pressure.
Take a throw-in short to a nearby player who is marked, then get it back first time, the thrower is free the moment the ball has left his hands. Use the free man to switch the ball inside or forward to a supporting player. Throw firm and to feet, and move to give an angle for the return. Rehearse it on both sides.
The instant the ball leaves his hands, the thrower becomes the only genuinely free player on the pitch. Nobody marks a thrower, because until he releases he cannot receive, and defences organise around players who can. That freedom lasts about two seconds and most teams never use it.
That is what the lay-back is for. It is not a safe option or a way of keeping the ball for its own sake, it is a deliberate return to the one player the opposition has stopped accounting for. A receiver who takes a touch first has usually spent the window, because by then the nearest defender has recognised the thrower and closed the angle.
Which puts the demand on the first touch, and specifically on not taking one. The receiver checks towards the ball, takes the throw on the back foot, and returns it first time. That requires the throw to be firm and to feet. A floated throw is impossible to lay back cleanly and is the single most common reason this routine breaks down.
The direction of the return matters as much as the speed. Laying it square gives the thrower the ball facing the touchline with nowhere to go. Laying it slightly inside gives him the ball already turned, with the pitch in front of him.
Worth being honest about the ceiling. A short throw-in routine wins a few yards and keeps possession. It does not create chances. Its value is that most teams lose the ball from throw-ins in their own half, and a side that reliably does not is quietly better than one that does.
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.