Originally Posted by claireauriga
One thing I don't understand - you were describing how his body might start to drift while walking along the track around the arena. If his shoulder is drifting in, does this mean his head is coming in too? If so, wouldn't a little tug (I say tug, I don't mean pulling hard, just rolling my hand back a little) cause him to turn inwards? I'm not really sure how all that works.
Well, this explanation will be a bit more complicated...so don't feel discouraged if it doesn't all make sense to you. I see you've only been riding for three months and you talk like you've been riding for much longer than that, so don't worry about understanding this. It will come!
Enough chit chat! Generally, when the shoulders drift in to the middle, leaving the haunches on an outside track, the inside shoulder is bulging (to the inside). This is either due to too much outside rein, unintentionally asking the horse to counter bend (bend to the outside), or disrespect for the inside leg aid. You should be able to tell which is the case by where the head is positioned in relation to the shoulders. If the head is to the outside, but the shoulder is to the inside, that means the outside rein is overbearing and is more active than the inside leg is, thus asking the horse to flex his neck to the outside. If this is, indeed, the case, then a simple loosening of the outside rein, inside rein check (which will realign the shoulders) and continuing to bump with the inside leg will remedy it quickly. On the other hand, if he simply doesn't respect the inside leg, he'll show it blatantly
by pushing his shoulder to the inside as well as his entire head and neck. And this is very rude, in case you didn't catch my drift (unless, of course he's never been taught, but that's a whole 'nother story). The easiest way to fix this problem is to bump/pull with the inside rein straight back to your inside hip to encourage his inside shoulder back into place, create an opening outside rein (hold arm out to the side and pull rein from there) to allow space for his outside shoulder to swing back into place and bump, bump, bump or even kick with the inside leg until he's back on the rail with the proper bend (then release!!).
So sorry to overload you, but you'll catch on quickly enough. You seem like a pretty smart, interactive rider. And I also know what you mean about not having your own horse to ride whenever you want. It does make learning and picking things up and little more of a challenge, but think of it as having a variety of horses to learn new things on. Most people who own horses don't have that luxury.