Plait as normal, wind thread round the bottom of the plait (going through plait a couple of times to secure it)..
Then roll/fold plait as you would normally, and stitch backward and forward right through to hold it together.
You either plait with a band and then put thread through and then up to the top of the plait pull tightly then fold in half and go back and forth the the roll a couple of times to make it secure or as above.
Plait to the bottom, then using a thread with a knot go through the bottom, once to the right, once to the left, repeat. leave the needle dangling and roll the plait up into a little ball. Go through from the underneath once to the right once to the left etc several times until the plait feels secure. Finish off going from the top through the plait and cut it off underneath so no thread shows.
I find using hair gel helps plait, an I separate the unwanted mane away with a rubber band. Chocolate ha a dreadful mane (springy and thick) and oftne we end up wrapping extra bands round the plaits, I'm surprise they don't weigh him down!
Oh, i'm sooooo going to be absent for the plait sewing part of the day tomorrow - my capabilities as a groom don't stretch that far!
Also going to be notably absent when it comes to taking them out - once took me an hour to get them out of Twiglet's mane, and my fingers were bleeding afterwards!