Why Is It....
Why is it if you have a couple drinks you walk better?
First of all, a little disclaimer. I am not going to advocate drinking as a method of helping MSers walk better. I am only answering the question as to the reason a couple drinks may help you walk better.
Anything that causes you to lose control of yourself, is not a good thing - especially when you have limited mobility or balance issues. I am not telling anyone to go out and take a couple of drinks to help them walk.
With that being said, my answer follows:
My answer to this would be that you probably are dealing with the symptom of spasticity. Many MSers have this very common symptom of multiple sclerosis. Quite possibly, the drinks may relax your muscles enough so that the stiffness associated with this symptom go away for a bit.
This may only be true for some people with MS and not all. If you take more than a couple drinks, the ability to walk may actually be hindered. Instead of being able to walk better, you may have less control over your walking, because now you have less control over your balance.
A couple of drinks may, as I said earlier, relieve some of the spasticity in your legs. This can cause you to feel like you are able to walk more smoothly. Unfortunately, drinking is not a smart "treatment option" for anyone. Especially someone dealing with a condition like MS, where you can lose your balance and fall at any moment.
So, the short answer, even though it may help, I wouldn't suggest making it a habit.