I love button/dressage braids.
One thing people forget to tell you - longer is better for button/cobra braids. I prefer six inches, unthinned/unpulled, but any length longer than 2 inches and shorter than 8 seems to work. I think you could get it to work with 8 inches.
I wet the mane down, brush, and divide the entire mane into equal sections (I prefer 4 fingerās length, or the full length of your pulling comb). You are laying down the footwork of the rest of the braid here so make sure it is 100% consistent. I loosely rubber-band each divide so that the mane stays out of my way as I braid down the mane. Pre-banding them before you braid them helps you visualize and see if the braid width is too narrow or if itās too wide, and gives you a good idea of what the final result will be. I generally can get 6-8 braids on my big gelding. More braids will flatter a short neck, and less braids will condense a too long neck.
I always start at the poll of the horse. I find some horses donāt like braiding and itās easier to braid their poll when theyāre first starting vs when theyāre fussy and sick of standing around (all told it takes me about 20m to braid so not too much standing around!).
Unrubberband your first selection and brush it out by pulling it above their heads and brushing - separate into 3 identical lengths and during the first few cross-overs of the braid, keep the mane held aloft and keep the crossovers loose (the looseness gives the braids that hooded look - braiding tightly at the base will not give it the same look) - after a few crossovers, bring braid back against the neck and braid downward, keeping the braid strands tight and clean. Rubberband the tail of the braid (tail =loose hair) back up/underneath the braid.
Rinse/repeat this with all braids (btw most horses are more sensitive about the hair on their withers - so go easy/loose on them there).
Now comes the fun part. Cut lengths of black thread (I like about an arms length same as you cut for hunter braids). Find your plastic needle, thread black thread through needle. (I totally put the needle/thread combo in my mouth while I do the next part but do not do this and blame me if you stab your lip/mouth)
Take tail end of braid and roll it towards the base of the braid - you can also fold (I wont be able to describe this well, maybe check a video for this part). If rolling, roll underneath the braid ā if folding, fold braid length in half, and then take the āendā of the braid and roll it/tuck it back to the base of the braid.
Holding the rolled portion firm in your hand, take your other hand and puncture the center of the roll with the needle/thread, pull the thread through the braid and back out the other side. Puncture the other side and bring the thread/needle back to you. Try to pierce where the rubber band was/is, for extra āgripā. Do this 4x and finish by snipping off visible ends of the yarn.
Rinse/repeat the rest of the mane.
Iāve gotten quite good at the braids thanks to COTH and the gentle critique of COTHers. 