Really, energy is heavy enough to be affected by gravity? Sure it isn’t the increased blood flow causing lightness?
He said head-stands. It’s where you essentially rest on your forearms, taking most of the pressure away from the head and neck. Often actually considered a more important pose than handstands and surprisingly easy to learn. Before that comes shoulderstands, where you (as comfortably as possible) lift up everything below the shoulders, then supporting your body with your hands, keeping it propped up.
Still, inversions have many contra-indications, mostly because of the massive increase in blood pressure in your head. So getting to 20 minutes may take a long time. I myself usually use an inversion table to hang upside down for 5 minutes daily (or whenever I need to wake up, a creativity boost or just want some more blood to my scalp in an effort to keep my hair). At some point I’ll probably get some inversion boots and hang freely from my pullup bar. It’s very good for the spine, since it allows gravity to decompress everything.
But the last time I did a proper handstand or even headstand is a while ago.
Without any inversions, practices like Qigong where you learn how to sense and guide the energy flowing in your body can help with this as well. You can sense the energy migrating to the groin and through some conscious breathing actually guide it back up, or at least away from there back to the spine. That often gives relief from the urge to climax or even have sex. I use it during sex to last longer (inverted sex is awkward). It takes a lot more practice to guide the energy towards more useful pursuits though.