For his forthcoming film, Shaitan, newcomer Shiv Pandit faced a lot of physical pain. For a particular scene, his character is tripping on drugs and is supposed to see a guy on the street flagellate or whip himself. While a professional was hired to play that part, Shiv took out his belt and started whipping himself too, getting into a competition of sorts.
The scene had many retakes and took about an hour to complete. By the end of the scene, Shiv had a visibly injured arm. A bystander watching the shoot eventually asked Shiv how his arm was bruised, while the professional artiste who had a thicker whip seemed healthy. Apparently, the secret was a cheat technique that makes it look like the person is hitting himself, but the whip actually cracks before touching the skin.
The length of the professional whip made it look impressive, but it was that, that gave the impression that it was hitting the body, while it only circled around. Unaware of this trick, Shiv was actually hurting and injuring himself.