Wait until you are peaking on MDMA and take one balloon of nitrous. There is no way anyone can say this is bad combo imo. It is pure heaven! Save the rest for the comedown.
It is very popular at raves where many people are rolling on MD so I'd assume it goes well. It was a fascinating experience on AMT, really enhanced the visuals... my mate was on MD though and really enjoyed the nos, though she did fall over!!