sometimes probably about 40 years ago somebody decided that it would be a great idea if players when tackled could get up really quickly, the acting half back be promptly in position along with the support players in order to catch the markers and defenders on the wrong foot, out of position, or even offside when the ball was played. Later, probably the next day, somebody decided that it would be a good idea to delay the tackled player rising to his feet in order that the markers could be set and the defenders be in position, maybe even causing the tackled player to drop the ball or make a poor decision in his/her frustration. The next day someone thought that it would be a good idea for the tackled player to wriggle around on the floor as if someone had speared her/him to the ground and for the marker to raise their arms despairingly and look imploringly at the ref. Watch any game from forty years ago onwards and you will see this. it would happen at just about every tackle and happens much less nowadays. For instance you can watch just about any footage of Shaun Edwards for a master class in it; and that's no disrespect to Edwards, he's just a prominent example.