As someone who was bullied and assaulted several times in school, I have to chime in: don't do that. A huge, arcing punch like that is flashy and spectacular, but it is easy to dodge or deflect (massive moment arm), and you'll be thrown off-balance. Instead, if you can get in close, aim for the gut, just below the sternum. Keep the fist low and close to your body, and twist your torso as you punch. Hitting the soft tissue below the ribcage and above the stomach is fucking painful and will leave the rubber sole sommelier struggling to breathe.