Some of you probably don't know this, but YouTube on your PC or laptop can actually be controlled from any smartphone, without installing any apps or linking the two over a network. All you need to do is use YouTube TV.
As Redditor circasurviv3 points out, it's a simple process. Just go to www.youtube.com/tv on your computer and press "S" to bring up the search menu. You'll get a prompt to pair your PC with your smartphone by going to www.youtube.com/pair from your handset and typing the code provided. And that's it, you're controlling YouTube on your PC from your smartphone.
Sure, you can probably install an app like YouTube Remote or even more elaborately control your whole PC with your Android phone, but this is a no-fuss, no-installation way that works with any computer and any phone, not just your own.
Use your Smartphone as a remote for YouTube on ANY computer | Reddit