Best Position for Glycerin Enema

What is the best position to get a 50:50 glycerin enema to flow up into the colon.

On the back with the legs as high up on the wall as possible to get a deeper penetration?

For a commercial glycerin microenema, I start in Sim's position, then switch to knee-chest for at least three minutes. From there, it's over onto the back for a minute or two, then finishing on the right side. This seems to ensure deep penetration and spread through the rectum.

If you are taking it solo, AlecJ's suggestions are reasonable.

If it's being administered by another, the knee-chest position for a teen or adutl, OTK for a older child, or diapering position for a young child.

Glycerin enemas are difficult enough to retain that I would think you would want to use the position that you can best retain most other enemas.

I have used Simms because it's the easiest to relax. For me relaxation correlates strongly to retention.

One that is close to the john

Knee-chest position.

Knee-Chest, because in that position the glycerin goes higher in the recipient's colon, allowing wider spreading of the glycerin and hence a more powerful urge to poo and superior results.