Hey, Tim.

Originally Posted by: Sleepers Hill

I just have a quick question regarding posture when playing guitar. I play with my guitar on my right leg with both feet flat on the floor.[/quote]

That's fine.

[quote=Sleepers Hill]However, I always find my right leg raising itself up onto it's toes and I find this much more comfortable.

That's not necessarily bad, but it can result in tension that can hinder your playing. I recommend avoiding that. If you cross your leg, that also leads to unnecessary tension & bad posture.

The primary fix to these issues is to use a strap. I cover that & proper posture in this tutorial.

https://www.guitartricks.com/tutorial.php?input=1141

A foot rest is also a good fix! This is primarily a classical guitar approach. But there's no reason you can't use one to play any style. The only consideration is that it doesn't help you transition to playing while standing, where a strap does. But if you don't ever want to play while standing, then it's not an issue.

https://www.guitartricks.com/tutorial.php?input=992

There are also these nifty tools that provide a different kind of solution.

https://www.thisisclassicalguitar.com/ergonomic-guitar-rests-support-ergoplay/

Hope that helps!