I worked with him today for about 15 minutes, (so darn hot). I stood by his shoulder and gathered the reins. While I pulled back on the bit, I pushed my hand into his shoulder and said back. Every time he took a step back I released the pressure and rubbed him down and spoke encouraging words and tone. I repeated it a lot.
After that I tried it in saddle and he took maybe four steps back before he got a bit confused again. Progress is Progress. But i'm wondering if there are any other simple methods?