Practicing being upside-down is more valuable than many realize. One simple-but-not-easy way to do so is in a Tripod position, as shown.
Place hands behind head, in as much of a triangle as you choose (the closer the hands are to the head, the more challenging the balance upside-down), move one knee at a time onto the same-side tricep, stay braced and engaged in the middle, and hold as desired. Work hard for seamless entries and exits, and add difficulty as appropriate.
Extending legs, then touching toes to the ground in an “L”- position are excellent ways to challenge and improve the position; And practice tucking the head and confidently front-rolling out if things go awry- which, if this is practiced frequently or in fatigue, they will.