It's not really the best idea to drop M two days in a row, you'll likely experience a far weaker high the second day due to tolerance from the night before, and your comedown and after effects will likely be much worse too. I think you'll regret it. When I go to multi day festivals, I usually choose a 2 or 3 drugs, do a low-moderate dose of one on the first night. Rest, drink fluids, eat. Take a low-moderate dose of something else the next night. Rest, drink fluids, eat, etc Then on the 3rd night, I either take a break or take it very easy with whatever drug I do decide to do that night. I never do the same drug 2 days in a row. I pretty much always come home from festivals feeling golden when I dose this way and I always have a great time.
It'll likely be a waste of your time dosing again the next night. Maybe find something else for the second night?