It’s to slow him down and to rebalance him. I have read to use your outside rein
i was told it was a halt with 1 rein, typically the outside one
I was taught it is where you do a small "pop" or tug on the reins, but not asking them to stop. You keep you're legs on, because You are just slightly reducing his speed and asking him to "half- a- halt". Understand?🙃
Because the horse to balance and slow
Squeeze on the reins and tighten your core
Think of it as a half go. You're going to squeeze the reins a bit and tighten your abs and butt it shouldn't be a huge movement or noticible just a little Hey, hello! To the horse
Just give a little more pressure on the reins, tighten your abdominal muscles and sit as heavy as you can in your saddle.