Granted that this is a little silly, but if you can get past that it might actually work for you.
When not overdone, horse stance is a great way to build leg strength, as well as to stretch muscles that can become resistant to stretching on a steady diet of walking.
But just 'sitting' in horse stance can be really boring.
My advice is to combine it with something else, like to occasionally substitute horse stance for a chair when sitting at a table or watching television.
Once you've built up the strength and flexibility to maintain a low stance for more than a few seconds, you may even find that this is more comfortable than most chairs, at least for a short time.
More importantly, so long as you don't overdo it, in other activities you'll be far less likely to injure your legs!
