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All you need is a level floor capable of holding the length of your body with your arms stretched out and you're good to go. Don't go to a class or anything because you don't need to be there for an hour and unless you live in a "trendy" area everyone will assume you're gay. Just do some basic stretches and hold them and you'll notice a big difference, I'd suggest 15 minutes for every 4 hours of sitting. Just do them while waiting/refreshing wf/reddit/email/etc.