Rub there for heads and give them more reins so they feel like they can breathe more
Take longer reins and then walk while petting and kissing him/her on the neck you can also compliment the horse like good boy well done and things like that.
Release of pressure, patting them, and then my dressage trainer carries sugar cubes in his pocket and rewards with sugar cubes, he chose sugar cubes because it's sugar and will melt in the mouth so the horse won't choke trying to eat it with the bit while riding
Release of pressure is huge! Timing with the release of pressure is a skill that takes time. But the pressure itself doesn't teach a horse anything, it's the reward of the release.
Giving the horse a little pat here and there is good and also saying ," good girl/boy"
Petting here and there after he did something correctly
Pressure, release, reward. The reward is in the release of pressure. Horses learn from the release of pressure, not the pressure itself. Timing is important, and it may take a little while for you to figure out the correct timing. That's okay. Hope this helps.