Me and a friend may be going to a week long festival. Would doing reasonable doses of 100-120mg twice in one week be detrimental? May also be using psychedelics in the interim the same week if that is even worse. As far as I know the M would be what I should worry about, as most psychedelics are somewhat safe to use regularly in the sense that you won't be severely physically hurt. I understand this isn't the case with M. I just wanna use it some and probably flip or save the rest.
Try to space out the instances of doing MDMA as much as possible. Take 5-HTP after your first roll, but stop taking it 24-48 hours before you take more MDMA to prevent the risk of serotonin sickness.
You should be fine. Not something you want to make a habit of though.