My buddy Fred occasionally uses both instant and extended release morphine
rectally. I believe this is how he does it.
1) A store brand enema to clean himself out
2) He smashes up the morphine in a piece of paper folded over so the powered can be dumped into the child oral syringe.
3) He adds a pinch of table salt and a pinch of baking soda to the powder. The salt prevents gelling and the baking soda changes the ph to match the rectum.
4) About 5ml of hot tap water is put into the syringe with the plunger removed and a finger covering up the hole in the bottom.
5) The powder from the folded piece of paper is dumped into the syringe and the plunger replaced.
6) He shakes the bejesus out of the syringe for a few minutes, usually until the water is cold.
7) After liberally lubricating the tip of the syringe with ky jelly, he lays on his side and injects the mixture about an inch in.
8) He removes the syringe (usually rolling onto his stomach to prevent loss of fluid)
9) He usually waits 10 minutes before getting up just to be certain no fluid is lost
10) He goes about his day without pain for the next 5-7 hours
Some other tips he told me about was;
Use a rubber band on the syringe to limit how far up he intends to push the syringe up.
If he is only using instant release, no crushing the pills is needed. Just place the pills into the syringe with the hot water and baking soda and wait ten minutes.
I can't stress the danger in this because the bioavailability is vastly increased. Until you know how effective this is, start with 1/4 of your usual dose.