The versatile and neverending use of the phrase can also be used as reverse psychology to say 'keep an eye on that'
Ruderboy: ''don't watch that, slag gave washing machine blowjobs anyway''
Rudeboy: ''you just poured ketchup on your apple pie''
Ruderboy: ''don't watch that, i'm blitzed''
Rudeboy: ''I heard your music video is getting played on bare channels''
Ruderboy: ''yeah don't watch that''