If you were wanting to start longreining but you had a pony that is terrified of ropes etc near its legs, how would you go about desensitising it to them?
You're right to recognise that your pony needs to be desensitised to ropes around his legs. However, before a pony can be desensitised, he must be sensitised to the ropes. In other words, your pony must be exposed to the feel of ropes around his legs before he can be taught to accept them.
I break horses to ride and drive, and I used to get a horse lunging nicely with a roller first. Then I would tie a heavy string or a light rope to one high ring on the offside of the roller, bring it over his croup, leaving enough slack to drop it over his tail and down to just above his hocks, and tie it to the corresponding ring on the near side of the roller. Then I would lower the string into position and send the horse on on the circle. However, this would often result in the horse having a good kick out when he felt the string behind, and some horses would really go for it and have a right buck.
I didn't like that idea for all horses, so now I train the horse in-hand to learn to accept ropes in preparation for long-reining. I do this by starting with training stick with a long lash, and start by flicking the rope over the horse's neck whilst I stand in front and slightly to the side of him. Some horses will accept this straight away, but some will move about a bit. If he moves, I try to stay with him and keep going. If I can't do that, I simply set him up and try again. Essentially, the aim is to allow the horse to feel the rope there, and to keep doing it until he stops reacting to it and stands to accept it.
From there it is possible, by rythmically flicking the rope over him, to move down his neck and over his withers, his back, his croup and then his tail head. By the time the horse is accepting of all that, he should be trusting enough for me to begin working on his legs.
Starting with his forelegs, I bring the rope, softly and with a constant rythm, over his withers and begin working down the leg. As before, if the horse moves around, I either stick with him and keep going, or set him up and start again, and work away until he stops moving and accepts.
Once he accepts that, I then work over his back and croup again, then start working down his hind legs. Some horses will have a jitter, and some will have a bit kick, but most are quickly accepting of it, having had all the experience of the previous work.
The initial laying on of the rope is the sensitisation, and the working away until the horse becomes still and accepting is the desensitisation. Of course, what you do with a horse on one side of his body, you should also do on the other.
As prep for long-reining, I then put the long rope, which is attached to the halter, over the horse's head, feed it along his back and drop it over his tail and, using the weight of the rope and a slight 'feel' on it, I teach him to yield to the outside rein and to follow the rope round to face me. I then change to the other side and do the same, so that the horse has learned to yield to both reins. This will be the means by which I will dissuade the horse from spinning in the longreins should he try.
All of the above can be done in an hour, with several short breaks in between to allow the horse to gain confidence and absorb the lesson.
I see you are in the north east of Scotland. It may be of interest to you that I run clinics and courses on this sort of work, either here in Angus, or anywhere with suitable facilities and sufficient interest. PM me if you'd like more information.