I'm new to guitar. Spent most of my time playing piano. I'm having issues keeping the guitar (acoustic) close to my body, when i play open strings. As soon as I go to play an open string, the neck will shift forward (away from my body). I have a guitar strap, but it doesn't seem to help the issue much. I just figured I would ask what I'm doing wrong, before I go much further with bad habits.

Thank you.