In practice when MDMA is taken with small doses of methamphetamine such as those found in adulterated ecstasy tablets (which many users enjoy), the user can sometimes reap the positive effect of both drugs, but also the negatives of methamphetamine such as jaw/muscle clenching, overstimulation and a nasty comedown. If the methamphetamine dose is slightly too high, then the MDMA will be overpowered.
True. However, "amphetamine" or "speed" has different meanings in different countries - for most of Europe, I daresay, "amphetamine" or "speed" refers to 'ordinary' amphetamine, a-methylphenethylamine - methamphetamine, N-methylamphetamine, is almost always referred to as meth. In countries where amphetamine is the dominant stimulant and meth a rarity, the amphetamine found in ecstasy pills will almost always be this.
Meth, in my opinion, would be a horrible addition to an ecstasy pill, as taken orally it has a very long duration, and its strong effects can indeed overpower the MDMA. It is also more potently neurotoxic.
Personally I find MDMA to be much cleaner and more enjoyable than methamphetamine. MDMA is probably the only stimulant I've come across which when pure, can provide a great afterglow and allows the user to fall asleep on the comedown. I don't see why you would want to tamper with that.
I disagree, but that depends on what you mean by 'cleaner'. The immediate comedown isn't as harsh, but a small dose of methamphetamine, to me, feels more clean in the sense that it is mostly clear-headed central stimulation. Larger doses produce euphoria and more peripheral stimulation, which no longer feels very clean - starts to feel quite toxic.
MDMA also feels quite 'poisonous' subjectively to me too, at least at larger doses, or if I've taken it in the recent past. I'm talking about pure crystalline MDMA here, not pills. Not only does it produce jaw/muscle clenching at larger doses, but I get an unpleasant psychological crash (compared to the more physical methamphetamine crash), followed by bouts of depression some 2-4 days after, colloquially known as the "Tuesday Blues", although this is preceded by a mild positive afterglow, if use has not been excessive. The fact that I can fall asleep on the comedown I would chalk up to it not being a very potent stimulant - MDMA on its own, particularly at larger doses, feels more sedative than stimulating, though during peak effects sleep is impossible.
Plain old amphetamine, particularly dextroamphetamine, is far cleaner than MDMA in my opinion: there are no psychedelic effects, no euphoria, just increased wakefulness, focus, energy, motivation. I also experience just about no comedown unless I go on a long binge; the comedown merely consists of peak effects having ended, but still not being able to fall asleep.
For these reasons, I would want to tamper with MDMA to use it as a party drug by combining it with a stimulating substance (amphetamine or a particularly stimulating psychedelic like LSD) because it makes me active and want to dance, and amplifies the pleasure of dancing greatly. If I'm using it in a chill-out or sexy-time setting, I take larger doses of MDMA and leave out the stimulant.
