Just read all of the posts in this thread, and not one person has mentioned what I consider is the best way for rectal admin.
Whatever drug you intend to use, dissolve it in a small volume of water first (for a pill, use say 3-4ml of very hot water to dissolve the MDMA) then let it cool to room temp; for 3-4ml, it'll take 30-60 seconds. Next, suck it up into a syringe (obviously without a needle), put the tip of the syringe just inside the rectum and slowly press down the plunger.
To absorb the drug through the colon wall, it first needs to be in solution. Instead of waiting for the drug to dissolve in water from the body, having it dissolved beforehand, means it gets into the bloodstream even quicker (it's onset is only marginally slower than an IM injection).
Admittedly it's not the sort of thing that you can even attempt in public, but a few mins preparation beforehand can do wonderous things.
I've never actually tried this method for MDMA (but haven't taken any - by any route - for over 4 years), but I have with amphetamine, 2C-C, 2C-I, 2C-T-21, IAP, methylone and AMT, and all with a fair amount of sucess (also tried it with morphine, methadone, opium solution, kratom solution ketamine and diazepam; all sucessful, but to different degrees). Only real disappointment was with THC. I'd managed to get the THC into an oil solution, which was then mixed with milk, and blended so that the THC was dissolved in the oily phase of the emulsion, which was then squirted up (fats are absorbed higher up your intestines by means of emulsification). Think it was most probably due to the colon having a tiny surface area per sq cm compared with the small intestine.
And for all those worried souls out there that think that putting anything up your backside (for enjoyment) will instantly turn you gay, get your girlfriend/wife to do it, then it can't possibly be gay; GIVE ME A BREAK. It's only gay if it's another bloke is pushing his dick, hand or whatever up for sexual gratification. Being gay is about having sexual feelings for someone of the same sex. Plenty of women will insert a finger into a mans arse so they can massage his prostate gland (it gets called the male G-spot) before ejaculation.
Actually, according to a good friend who is gay, people who make a huge fuss about "nothing goes in there", are generally doing so to try and cover up guilt associated from repressed homosexual desires ( as in Shakespeare's "methinks the lady doth protest too much"). Apparently it's also the same deal with people who go "queer bashing" - they can't even be honest with themselves