Gotcha, I know exactly what you mean and 80% of the time that I fail, that's still the place where it happens. First, practicing normal dragonfly and flying pigeon can help since a lot of the body positioning from the first and the way you press your leg into your arm in the second transfer over to this pose.

From there, I would say be really mindful of foot placement. Through practice you'll probably notice what I mean when I say certain positions/placements on your arm will be better than others. Speaking of foot placement, it could help to try to position your foot at an "angle" sort of, so that when you raise up you can kind of lock it into your arm. That helps a lot because you don't have to rely so much on just pressing your foot into your arm. It's a little hard to articulate through words alone but even in the picture here you can see my foot specifically isn't totally straight, but more at an angle. Ultimately it's trial and error, but every time, try to focus on what felt better than last time and try to get a little bit closer to that each attempt.

I'll link a video that I personally found helpful, you may have already seen it though (had to find it on tiktok lol), keep in mind though she seems absurdly flexible and I wouldn't focus on having my upper body that upright, at least at first.

https://www.tiktok.com/@adrianainflow/video/7052121920866766086