Density

I would like to try a mixture that is denser than simple water, but without adding something that could be too unpleasant. something like pectine or hydrolized cellulose to make the fluid almost sticky. feeling it both flowing inside and out, and the sensation of something thicker filling me up is what i'm searching for. Any suggest?

Potato starch comes to mind.

I don't know, potato starch always manage to settle down in the bag if the inflow is to slow and i also fear of messy release as it can settle down in the curves of my bowel and mostly release water and i imagine the starch staying for too long there as it wont collect water from my intestines

Have played with all kind of "dense" fillings...starting with warm chocolate or yogurts, up to puddings...we tend to use sugar free...I suggest the use of a large decorator siringe to push it in.... of course the purpose pf the game is to watch it come out... Jello is a lot of fun...A few rinsing are also required if you want to get rid of residuals...

I used to enjoy using oatmeal, taking maybe a cup of instant oatmeal and soaking it in a quart of boiling water then once it’s cooler mix with about another quart or quart and a half until it gets to be the right temp and consistency. Sometimes I’d blend half the oatmeal into powder before soaking. I would expel into a bathroom trash bag as I’m not sure if all that oatmeal could lead to clogs or otherwise harden on the pipes (prob not but just being careful)! Also other potential options are a product called Thicken-it (used to thicken beverages for medical purposes) or also corn starch.

Warm milk and eggs. The more eggs that go in it, the thicker it becomes. It is slippery, sticky, and gives nice cramps after it's held for a bit. Pooping it out is an experience.

Be sure to clean your enema equipment thoroughly after with hot water and dish soap , and rinse it out well with hot water. or it will become smelly and gross.

Try a product called Thick-It or Simply Thick. It's available in some supermarkets and drugstores for sure. It's something used by people who have swallowing problems. It's a food grade product. The thickness is determined by how much powder you use. If you fill a syringe with water and then put the powder in and shake the syringe your good to inject. Don't wait too long because it will thicken in the syringe and be hard to injection. I use a feminine syringe because it's easy to fill and mix. Good luck. Drop me a note if you try it...

Try a mayonnaise enema. https://en.zity.biz/index.php?mx=gallery;ox=showalbum;ax=7998