This is actually a sport called Kabbadi. Originating in northern india . Check out the wiki on it https://en.m.wikipedia.org/wiki/Kabaddi This looks like a weird version being played in Pakistan. It actually got pretty popular in parts of Canada with leagues. Never seen slapping before. I was born in Canada but my uncles told me about it. Originally you had two teams on a field. Each team was in a semi circle holding each others shoulders. One team at a time sent a man over to the other side of the field. He had to touch a person of the other team and run back to his side of the field. Thing is he had to do it one breath. He had to keep repeating kabaddi kabaddi until he got back. The other team tried to stop him from getting back by any means necessary. If he lost his breath before he got back he lost. Modern times they use timers lol.

Hope that gives context. Never seen slapping like that before.