Here's my input:
I was at EDC vegas a couple weeks ago. I took 200mg MDMA on the first night and rolled very hard. The comedown was fine, and the next day I was feeling a little tired but nothing out of the ordinary (after all, I was dancing my legs off for 6 hours!!).
The next night, I took 200mg again and didn't really feel anything after 1hr:30min, so I took another 200mg. A couple minutes later I was rolling on another fucking dimension. This was the first time I ever experience eye-wiggles, and that sort of thing.... it was AWESOME.
Again, comedown was fine and the recovery back to normal alertness/function was about a day (this is including jet-lag, etc.)...
Rolling two days in a row is not much worse than rolling one night IMO; just make sure the substance you have is clean...
OH, I should mention that my jaw was EXTREMELY sore the next couple of days.... first time I experienced that too... sucked... I normally don't clench and didn't realize I was even doing it!!
Good luck to you