I see that a few people checked the link so I'll post the answer I got just in case someone is interested!
I had a private yoga class yesterday and it was a-ma-zing!
She told me a bit about her own IVF struggle (7 years!!!), so she completely understood my tmts and adapted my routine accordingly.
Which brings me to important info about exercising after ET. She checked with her yoga master, and he advised to stop exercising completely after ET. Her master suggested a 10-day "quarantine", she suggested 15 just to be sure. Apparently, it's super important not to put ANY pressure in your pelvic area during implantation time. So between ET and the first beta, all you can do is breathing exercises (feeling your pelvis, ribs, then collarbones, and tibetan breathing sitting on a block or on a chair). And the end of that quarantine, a few days before beta, you can add a very fun pose that relaxes your back, opens your hips and increases blood flow in the pelvic area. You sit with your whole side, leg and shoulder against the wall, and then you twist towards the wall and lie on your back with your legs up. You place the soles of your feet against each other, toes included, and you bring your heels as close to your pelvic bone as you can. You rest your hands, palms up, on each side of your hips and you breathe into your pelvis. it's an amazing posture, super good during AF, and you can keep it for as long as you like. It's good to have a towel under your head to make sure your chin is tilted towards your sternum a bit (so your forehead isn't tilted back).
Between your BFP and heartbeat u/s, you can slowly add more poses, but it's very gradual. I think the breathing exercises will be very good to just "be" inside my body, relax and be aware of what's happening. Keep a peaceful attitude through it all. I realize that meditation, breathing and walking are indeed just enough to keep my body healthy and aware without putting the delicate implantation process in jeopardy. 10-15 days is nothing compared to all the years of tmts, waiting, and so on, and all the years I have before me in this life. Compared to a whole pregnancy in which I'll be able to do most of the exercise I want to do, it's nothing.
So there you go. I've decided to follow her advice not because I'm scared too much exercising will cause a BFN, but because I want to help my body and respect the pace it needs in that delicate phase of the process. When I look at it this way, I find it touching and beautiful.