I have no experience with that tool but it appears to be a scraper so presenting it 90 degrees to the wood should be correct. One thing that's really important with swan neck type tools is to keep the tool rest back far enough that it is supporting the straight part of the shaft, not the bent portion. That should reduce is tendency to torque in your hand. The shaft should be horizontal and at center height. You can err on the side of having the handle very slightly raised but don't lower the handle.
Some more details or pics of exactly what you are working on and where you are having trouble might help you get some better advice from some some smarter folks.
Hope that helps.