Yes, I have one this quite often over some years. I like the sensation of being stuffed and then of the relief that a good big enema brings!
Immodium is too expensive; but in South Africa there are generic drugs that contain the identical chemical (loperamide) at about a tenth of the cost. To stop me up thoroughly takes ten 2 mg tablets a day, taken at regular intervals. Loperamide has a ten hour half life in the human body, so it doesn't much matter whether you take two at four hour 48 min intervals, or one every two hours 24 mins. Getting the intervals dead right isn't an issue either. And you may find you need far less, anyway.
My best effort has been two weeks without a BM, starting from empty after an evacuant enema. Other drugs that work include codeine phosphate syrup, obtainable without prescription here. But be careful of that one - it IS addictive and it also makes you feel light headed. Stop taking the loperamide about a day before you plan to take your enema. Then take senna instead, about 10-12 hours before enema time. If you like cramps, take lots!
It takes patience to get a big enema in on top of all that's inside you, but don't give up after just a quart or two. The resulting expulsion is impressive to say the least, but also very tiring and needs a fairly strong purgative enema to get rid of it. Be aware that it will block even an old-style toilet (The turds are humungous and very hard) unless you take precautions!
As I am quite strongly anally erotic, I also like things shoved up my rectum, and the bigger the better. After years experimenting with various objects either natural or home made (including plasticine 'turds') I have found that nothing beats a butternut. My anus will accommodate them up to 10.2 inches in circumference at the widest point (equivalent to 3.25 inch diameter).
Most of us are afraid to shove anything up that might 'get lost' but I have not found that to be a problem. The usual shape of a butternut is a wide bulbous end with a narrower neck. A suitable sized one will be from 4-9 inches long. Funnily enough, I find that longer ones are less likely to resist expulsion than shorter ones. The trick is to shove the butternut in wide end first, and then push it further in after it is fully in the rectum with a suitable object like a shampoo bottle with no sharp edges. I will feel a resistance as it encounters the 'flap' that separates rectum from descending colon, and then a release with further gentle pressure as the object slides up into the descending colon. There it rests comfortably, and I can feel it as a hard lump through the wall of my abdomen.
It isn't immediately possible at that point to expel it by bearing down, and that may seems scary. But I can press down and inwards on the upper end of it through my stomach wall, and feel its thinner neck enter the rectum again. With continued shoving, the urge to evacuate will assert itself (this only happens when the RECTUM, not the descending colon, is full). Then I can pass it out easily! One thing to note (but not to worry about): a man will likely find a large amount of prostatic fluid sq
But supposing it DID get stuck? Well, it's a vegetable! I did once get an exceedingly big one stuck! It didn't have a thin enough neck and would not go back down into the rectum. So I had to wait until it rotted. This took 17 days; and while I admit I was uncomfortable, I didn't need to go to a clinic and have it removed. Even this very big one wasn't enough to stop me farting. When it finally did rot enough to soften, it and a whole lot more came to light quite OK.