Agreed. This is similar to Rabbath's idea without the bent endpin and I have used it for years.
If you were my student, I'd advise you to take a step back and let the bass lean more into you when in TP. I don't often play standing, but on the occasions that I do TP is the only time I'm truly comfortable because I can lean the bass back into my collarbone and not have to support it further to keep it from falling. With the bass in this more angled position, it is much easier to get around the front of it to apply downward/inward weight to the strings without an over extension of the shoulder.