Eye dimple suggests he doesn't have optimal hydration and/or humidity, so you need to check & work on improving that.
As for him staying "upside down", he looks to me like he held that position entirely in self-defense, which means he's fully in control. What we worry about
is when they lack either the strength or co-ordination to turn back over, as that suggests serious illness and/or neurological issues. Looks to me like he just
wants a piece of you, lol. I believe what your seeing translates to "I DARE you to get closer!"