You can practice with a dildo at home instead of waiting for hands on time with Him - a double length one, or something longer than 12 inches so you have a "stick" to hold onto the "lollipop" is good. :-) As MastersBitch96 said, use a lot of lube - it will help tons. As you practice, try and flatten your tongue, relax and suck on the dildo pushing it further back each time. Test where your gag reflex is and learn what it feels like - where your breathing gets cut off, etc. Just keep practicing keeping your tongue down, getting used to the feel of it in your mouth. When you feel comfy there, try and get it all the way down. Easiest if you either inhale or swallow it down - it's a very natural thing for your body to do - it's your mind you are training. If you are worried about gagging and/or thinking about choking the entire time - you will. Mind over matter. *grins* You can always take it out if you cough or can't breath - take a deep breath and try again. Again, lube really helps it slip past the back corner of your throat. It's usually easier if you take a deep breath, hold it and then swallow, keeping the dildo there until you have to breathe. Ease back to where you open your airway again, breathe and repeat.

By practicing on a dildo, you take the performance anxiety and stress out of the situation...plus, it's thrilling to practice something for your Master, knowing that you are working to please Him. At least, I think it is.

Hope that helps, and remember practice makes perfect. And I'm sure He won't mind offering Himself up to all the hours and hours of practice it takes for you to get it right. By the sounds of it, you are doing famously already. :-)