Why put some things up your ass? Well, many things are more readily and better absorbed through the rectal lining than the nasal membranes or stomach lining. More buzz for your buck. Is this true or all drugs? I doubt it, but I don't know for sure. I know it is for MDMA and many opiates (i.e. supositories (SP?)). Granted I.V. is usually an even better way to ingest drugs, even more buzz for your buck, but it's also more dangerous, especially for those of us who don't really know how.
Regardless of why, I'm not sure if meth is more effective rectally. Sorry.
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~I live to learn and learn to live.
~"I'd rather have 30 minutes of wonderful, than a lifetime of mediocre."