I’ve done it but I haven’t made it past 48hrs, I’m 20hrs in right now it’s usually the second day when I rinse just watch not to swallow as it very tempting. I’m aiming for 5 days minimum hoping for 7 depending on work situation
Of course not, be reasonable, your body needs much more water daily than the less then ~1ml it can absorb when you clean your mouth. Also please take a shower when necessary, do the test, scale yourself before and after shower and be amazed by the ~zero grams you’ll add, just don’t have a bath shower and be fast under the water, if you wash your hair dry it out blowing or your body will have a lot of time to absorb that excess water. But come on, don’t be a fat, sick and now dirty and stinking person. Keep at least your personal hygiene up to date.