This is not to say you literally need to block the quick free kick when it’s taken, it’s more you have to prevent the quick free kick by standing in front of it. Stated in a simple way: Don’t let a team take a quick free kick. Force the other team to wait until your team gets back to defend. One player should stand in front of the ball until their team is ready.
The referee will eventually force you to move away or give you a warning about a yellow card, but this will give your team a bit of time to let your team get prepared. If the referee does give you a warning, next time be more subtle or have another teammate slow the play down by standing if not right over the ball then a few yards a way. Use your best judgment though, it’s not worth getting a second yellow.
But time and time again you see a team win a free kick and play a pass down the line and then get a quick cross in and score a goal. Don’t let this happen. Give your team time by holding up the other team from taking the quick free kick with a bit of gamesmanship.
Slyly stand in front of the ball and delay the play so your team can recover. Momentum is a killer, who has it many times ends up winning, who doesn’t of course plays the role of the losing team. A quick free kick can often turn the momentum to one team; don’t let that happen to you.
Basic defending in free kicks.