"Now, for the masses: how does one accomplish this?" Ah--that is the question, isn't it, BBinder? It's a life-long pursuit for many of us. Helping people discover and increase their skill at these turns is the art and science of great instructors everywhere.
All I'll say for now is that the first key is have the image of the Infinity Move in your mind from the start. Know that this is the flowing, gliding, continuous motion outcome we're striving for. Make sure that intent matches the technique. This is arguably the biggest missing link for most recreational skiers, at all skill levels, who think of their skis primarily as brakes and their turns primarily as a way to slow down, to "stop going this way," rather than to "go that way." The Infinity Move maximizes gliding, not braking--it is the embodiment of what the great French technician and author Georges Joubert called "glissement," which translates roughly as the desire to glide, to "ride a fast ski," to ski whatever line you choose to ski as fast as you can, while choosing that line deliberately to eliminate the need to control speed with your technique. The Infinity Move is all about offensive, not defensive, technique, managing speed through tactics rather than technique, keeping the skis going the direction they're pointing as much as possible, using the edges to hold the line, rather than to scrape off speed. It's what I call the Go! Factor, and it's missing in 90% of recreational skiers, at any level of skill. For most skiers, this type of skiing requires a paradigm shift at the most basic level of how they think about turning from the start.
Intent Dictates Technique. Even when they "think" they want to develop the technique of great skiers, few skiers, outside of racers, operate with the offensive intent that is the pre-requisite of great technique. As you know, I've written a lot about "skiing the slow line fast" in the past. Note that it is not about "skiing fast"--it is about the desire to ski fast-ER, all the time, to gain speed when you release the edges and dive down the hill, to literally ski whatever line you choose to ski as fast as you possibly can. But "fast" and "slow" are states of mind, and the actual speeds involved will vary from skier to skier, and from turn to turn. The only way to "want to ski faster" all the time, of course, is to ski "too slowly" all the time. Whether it's you or me or a beginning skier going 2 mph or Lindsey Vonn going 90, the mindset (intent) must remain "how can I glide faster on this line?" The moment that changes, the technique of The Infinity Move goes out the window.
I do not turn to control speed. I turn to eliminate the need to control speed.
Once the mindset, the intent, the basic paradigm of turning to control direction rather than speed, are ingrained, there are many ways to help skiers develop the techniques of great skiing. Progressions, terrain choice, tactics, focuses, teaching styles, and so on are the tools of the trade, and great instructors master these tools to great effect. But so many lessons fail, simply because the instructor tries to teach offensive techniques to defensive skiers....
Best regards,
Bob