I’ve seen this movement practiced sometimes within surya namskar sequence ( a few times on the odd video) that goes like so-MOVE into lunge, then while stilll in lunge
go into trikonasana with legs still iin lunge - the waist/upper body move innto triangle, then reverse triangle.
Then do the other side.
Not sure if this a “bone fide” asana, though i felt pleasant sensations inthe waist and mildly energising.
And i’ve saw a few folk do it on video. halfway through a standard SM,
None of the limited teachers i have had , have shown this movement/position.They may have come from the more stricter classical or iyengar schools but still flow style. Good teachers ,but this pose looked like it might be good for you.
I’ve always felt my practice was possibly too rigid .(practicing reinforcing habits or poor postural patterns held there by brain-level reflexes, rather than yoga)
Maybe you can shed light on this,like prayer-pose twist while in lunge( in relation to the legs) but you instead open up (& rotate) the shoulders,arms and waist just like in trikonasana.Also reversed and then the other side done
Lower body-lunge. Upper body-trikonasana
Roughly speakly.
One girl did place leading leg on a step type reebok block( Throughout SM) but i’m pretty sure a few others did’nt.I believe the back foot was straight.(Though could have been at a very slight angle.)
I did it once.And i felt alright.
I am aware one of the old texts, HYP perhaps, says asanas are intuited naturally, through their effect( prana-wise,opening etc) by seasoned yogis.Meaning they did’nt have to consult the manual for another asana to ‘try out’ let’s say…Just like a composer or artist say, they had a natural sense of asana, what worked( anatomically, energetically) They did’nt have to think about it.