4given -
There are several positions that I would check beyond hip:
1) Stock tucked underarm with the firing hand as far back as possible - essentially with your thumb touching your chest. Try it at different angles. This is one way to 'shorten' the shotgun in tight quarters and also as an emergency close range mount;
2) Turn sideways and position the shotgun across your chest, muzzle down range, in this position the shotgun stock should be unsupported with your firing hand holding the stock by the pistol grip and the stock running outside your forearm. This replicates shortening the shotgun to clear a tight corner AND firing across the body from a supine position. For a right handed shooter the ejection port should be up/away from the chest, but all corners aren't right handed and there is no guarantee that you will end up supine positioned for a strong-side shot so do it support side also. A lefty needs to know how much 'roll' to give the shotgun in order to ensure ejection.
3) Do the above with the toe of the stock mounted off the shoulder and on the upper arm, above the bicep in the armpit (poor description, I know).
Here is what I know about how to hold shotguns:
I was taught the push the forearm forward while pulling the stock into the shoulder at a Smith & Wesson police shotgun instructor course in the mid-80's. Wow! the light switched on, give me them slugs and buck. The S&W guys said they had been taught by John Satterwhite. We immediately adopted the push-pull into our shotgun training.
Subsequently, I attended a shotgun instructor course at the H&K ITD, and was introduced to the HK/Benelli M1 Super 90. I found that push-pull worked with the M1. At the time there was a myth that you didn't want to mount a sidesaddle on an M1 because it wouldn't run with light or reduced loads. Couldn't prove it by me, I don't recall ever malfunctioning an M1 or Rem 11-87 (gas operated but with a rep for not reliably cycling light rounds with short barrel).
Bottom line is firmly holding the shotgun using push-pull limits the shotgun's movement enough to allow reliable function as well as reduce recoil.