Anchoring inside of forearm
 

on the Guitar body..

Do you think it hinders good technique?

If it's anchored, then yes. But just touching the guitar is unavoidable. It's only anchoring if:
1. Your hand/arm is in a fixed spot and needs to be in that spot in order for you to play well.
2. It increases tension.
3. It limits your range of motion.

If even one of those is met, then you are anchoring, which is bad.

Just gonna quote this for the goddamn truth.

Yeah rekon it's all 3, didn't notice I was doing it until I started to feel pain away from the guitar, after playing my Les Paul BFG, with "sharp" edges.

So now I need to work on getting my forearm away from the body. I guess I will concentrate on just resting the palm on or behind the bridge.

Thanks