Learning how to ride with a dressage whip?
I am a returning rider (trained as a kid/teen in hunter/jumpers) and getting re-started riding dressage. I am having all kinds of trouble getting my coordination together enough to manage a dressage whip. The horse I free lease is also going through something of a re-training herself, and is not great about leg aides and has a tendency to drift off the rail, so my instructor really wants me with a whip in hand to "reinforce" my leg aides.
My specific problems (the biggest two, there are probably others):
1. I absolutely can not handle my reins, ask for a leg yield, and simultaneously use the whip in the correct "right behind the girth" location when we start drifting off the rail. I either lose all contact with my inside rein, end up hitting myself with the whip, swing wildly at the air and get nowhere near the horse, or all of the above. What suggestions do you have to practice this and get the coordination down, particularly while maintaining rein contact?
2. Switching the whip while switching direction- I'm sure I'm not the first person who can't do this, but it's really ugly so far, and as soon as I start thinking about doing it, I lose all concentration on everything else and in the blink of an eye, my horse is ducking off the rail and in the middle of the arena. I've watched my instructor do it both on the ground and on the horse, but I feel hopeless that I'll ever get it. Practice tips?
I'm working on so many other things right now, the whip feels like an unnecessary accessory that's getting in the way, but my instructor feels that the lack of responsiveness to my leg aides really needs to be addressed. I do trust her and want to be able to put all these pieces together, so I hope there are ways I can practice on my own so I can be a little more focused during my lessons.