Well, everyone acts different online than in real life. People always say that you should only do one dose. But when you are high in the sky with the magic flowin', and it starts to fade away at a festival with your mates, with a bag full of crystals in your backpocket... are you seriously NOT going to redose? Well, shit, if people took the time to read for 5 minutes on erowid.org, they would find one of the effects of MDMA is "Strong desire to do more when coming down". It's simply your brain that is just set on doing more, wich is why it's really hard to not redose, when given the right oppurtunity.
Doing more MDMA after the first hit is of course more dangerous in terms of long term damage, and the day after gets more tiresome indeed. It also adds alot to your tolerance wich makes the effect of the drug weaker the next time you do it.
Every time I have done MDMA, I have redosed at least once. Mostly only one redose. Every time I did it, it made the roll last longer, it "put me back in that place" so to speak. Not as powerfull as the first comeup, though, if I remember correctly (2 years since last roll now).
It also makes your mind alot more messed up, you start to act alot more tripped out. You will sit and talk about so many lovely things with your friends, and then suddenly realizing that you are all speaking nonsense. It's like going from being REALLY interested and into the conversation, to being really unintersted and suddenly bored. Thats when the second comedown kicks in. You and your friend(s) might feel really stupid or lame, tired and maybe a little depressed that life isn't THAT great when the drugs wear off. Thats the time to just let it go, and be thankfull you had a great trip, and know that you'll be fine tomorrow. I reccomend to smoke a joint at this point, if you like cannabis. Good cannabis CAN prolong the effects, it happened with me at least. The 2nd comedown hit hard, and I smoked a big bowl of weed from the bong, and the effects of MDMA just came back! Like, you just feel the good sides again. This way you can keep the good effects longer, and NOT redose anymore. You can also do this after the 1st comedown.
A small percentage of the MDMA turns into MDA, wich is far more psychedelic. So if you do enough, you'll start hallucinating, seeing people who aren't there perhaps, seeing hats on people heads wich are not there, beards that dont exist on peoples faces. I saw my friend walk across the floor and enter the bathroom at a house party, only to turn around and see him still sitting in his chair. I also saw a guy outside of the window, who ofc, wasnt there sunday 7 o clock.
That night I left the party really scattered and threw up alot of water, and fell asleep in my bed hallucinating with my eyes closed, seeing beutiful things. All of the time my mood was still good and happy and not afraid. But for others this could be scary..
If you have real MDMA, you will not die just because you eat a couple more doses, but you need to stay hydrated all the time, and keep your head with you and realize that you're on drugs. Not everyone is capable of this, and thus, it could lead to bad things. Like getting into a hospital, or actually dying from dehydration :O I think thats a long shot though, the big risk is adultarated drugs.
My experience with redosing also tells me that it will make you stop using the drug faster. I just realized one night after doing it two nights in a row, that the drug is unforgiving and best left sacred. MDMA is not for using a lot. It's just not worth it. Because no matter what we tell ourselves, the brain dont like too much of that stuff. It's just not good. The effects feel good, and you can get alot out of it, but yeah, its a drug and it will suck you in, if you're not careful. Its easy to do a drug, but hard to it the right way.
Dont waste your MDMA tolerance on mediocre festivals or at parties with friends you only hang out with when you're high.
MDMA is best used with close friends, on very rare occaisions.