Could we broaden it a bit? Why do either enemas or suppositories? The politically correct answer wont do, you know! Getting clean is all very well, but it should also be fun. Both of them cause all sorts of delightful sensations - and common to both is an urgency to expel that many of us find delightful. Actually, I think ALL people like that - otherwise we'd find more urgent stuff to do and get horribly constipated. But taking a dump is nice, so we don't put it off. By extension, the feeling of needing to go is also nice, since we know we're going to enjoy this when we get there!
So, to get that feeling of needing to run to the jazz, take a suppository or an enema! Kudos to the creative suppo fans who make their own jumbo sizes - condom size is grreattt - and you can retrieve it and use it again, even sprinkle Tabasco on it for more zing! Kudos, too, to the learned masters of fiendish recipes that cause instant explosions, or have you writhing on the floor with cramps; and also to those who brew the milder potions that can make you feel pregnant all day (can't do that with a suppo!).
However, other things can be shoved up the exit ramp that do the same and offer different (but equally interesting) feelings. I'm not talking here about fruit like cucumbers used as anal toys, but about things that vanish inside you and leave you wondering how the hell you are going to get them out again! That's a groundless fear, by the way. I never heard of anything except unnatural stuff like bottles getting stuck. Mostly you can feel what you eased up you through the abdominal wall (that's quite fun, too).
For instance, there's a humungous thread about bananas on this site (a lot of it due to my interest); but others have told us about grapes, small tomatoes, apples and other fruit. At the larger end of that scale, I like butternut squash shoved up me entire. Providing the effective diameter is less than 3 1/4" these feel fantastic both coming and going, stroking the prostate lasciviously as they do it! And they certainly do provide the feeling of needing a shit, plus an awesome experience in doing so.
One caution: if you are ging to do fruit or veggies, make sure you have washed off the bloom on the skin first, or at least killed it with a bleach solution! Fruit skin usually hosts yeast in enough quantity to give you a yeast infection, either internally or on the perineum or even the penis or vagina. Both are nasty (Comment, please, Susie?).
So: if you send a banana up the chute, have you inserted a suppository? I say you have - the sugar will make you go very shortly! If you send ten or twenty, have you taken a banana enema? Why don't you try it and see?
Johnny