If you are talking about plugging base, then think again. Anything containing solvents, or that's too acidic, could be extremely irritating to the bowel. If it ain't crystal with NO smell, then I would suggest at the very least that you purify it before wrecking your rectum.
~~~~~~~~
A neighborhood priest happened by one day while Little Johnny was dripping something on ants and laughing as they frizzled up
Priest: What's that you're playing with Little Johnny?
Little Johnny: It's acid.
The Priest, thinking he must attempt to get the acid off Johnny, said:
I'll give some Holy water in exchange for that acid
Little Johnny: What's that good for?
Priest: Well, I've put some of this on a ladys tummy, and she passed a baby.
Little Johnny: Aww that's nuttin'. If I put some of this on a dog's arse it will pass a V8
~~~~~~~~~~~~~~~~
The rectum will be fine for absorbing speed, providing of course you don't jam a big crystal up there. Powder first, then use a gel cap as outlined for MDMA.