Have you got a neck strap, leadrope or martingale you can put on? If you're nervous, you can hold on to those instead of tugging on his mouth, and it'll make sure feel a bit safer I'm sure! Well done on the first bit though, its just time with these things! Plus side, it got better :)
Keep us updated!
One possibility to consider - there is nothing wrong with borrowing or using a stock saddle (western or Australian - Aussie being better for working up to English) while trying nerve-wracking things.
Not long after I started riding, Mia bolted while I was dismounting and I landed back first on some rocks. Over 3 years later, it still gets sore there when I jog or ride. And in my 50s, I don't heal as fast as I once did.
Frankly, I would NEVER have learned to sit the trot using an English saddle. I was too nervous, and nervous makes tense, and tense means it won't work. However, after learning in stock saddles, it all made sense when I trotted in a jump saddle.
This last week, I finally tried cantering. Intentionally. Trooper hadn't cantered with a rider for a year, and my cantering experience was limited to brief moments prior to full-out bolts on Mia, so my body & mind associate cantering with out of control bolting. And right now, you couldn't pay me enough to get me to canter in an English saddle. At least, not my jump saddle. I'm getting some spectacular bounces in my Australian saddle, and getting some valuable help at times with the horn...without a doubt, I'd have gone flying off Trooper's back if I had been in a jump saddle.
Mind you, I still have my jump saddle and I plan on keeping it! There will come a day when Mia & I will do loops cantering while using it. But I don't have any calm horses to learn on - calmer than Trooper, that is - but a supportive saddle was pretty nice when doing my first canter on a horse that hadn't cantered with a rider for a year. He misjudged a few turns, and I wasn't helping him much at the beginning, so we had some very sharp turns while I was still flying 6 inches above him.
But the nice thing is that success relaxing with a secure saddle carries over to a less secure saddle. And with trotting, I found I sometimes needed to just keep trotting, even if a bit off balance, until my body got tired enough to relax. I tend to think of my Australian-styled saddles as training wheels for arena riding. I'd love to buy a really good one someday...
First attempt for me, first in a year for Trooper. I spent years flying in F-4s & F-111s where I had less air under me than I did that day with Trooper !
I totally understand your fear - I think many people have been there at one time or another. When I'm nervous, sometimes it helps me to have someone else ride with me. I also listen to music or sing to myself. It'll help you relax a little bit!