So long as you don't wake up in your neighbor's closet, suspended upside-down from the ceiling in that position, you should be good to go, unless that is, you wake up smiling. But hey, to each their own. Sometimes though a bat is just a bat, an not a omen, and sometimes your body will initiate spontaneous kriyas. Seriously though, meditate in that posture. Invoke it. Not only is the position comfy but it is also instructive. Using various body postures as mudras, both in magickal practice and in ecstatic trance induction has a long history. It is well worth studying.