Damn you all!
😁
This thread has got me thinking about all kinds of methods to 'automate' an enema!
If we ignore pumps for a moment and only use tried and trusted gravity to get the liquid of your choice to where you want it to go, then I think these have some potential:

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Garden watering system
and I selectively quote:
Suitable water temperature: 0-40 ℃ - excellent as I don't want anything warmer and ice wouldn't work!
Power supply used: 3V, AA battery - fine (you'd need to be careful about them going flat though...)
Working pressure: 0.0-4kg - Hmm... pressure as mass? Surely PSI or Bars or Pascals either way, using gravity and common sense, no issue
Watering times (can be controlled by the rotary switch), the specified mode continuous output, the shortest valve opening watering time is 1 minute, the longest continuous output valve opening watering time is 240 minutes. - OK, so the longest is no use at all, but 1min (or more depending on tastes and capacity) seems fine.
Watering cycle (can be controlled by rotary switch), the specified cycle time, the minimum cycle time is 6 hours, the maximum cycle time is 7 days. - OK, initially this confused me, but I think it means that the cycles (1-240min) must be at least 6 hours apart, so this limits the device if you wanted to build an enema in short (1minute) doses...unless you plan for it to take at least 6hours!!!!
Obviously this is set up for hosepipe fittings, but that's easily fixed. I think the biggest limits are the practical ones of only 1 cycle and no remote control, plus it's an 'enema in' only - no pumping in/out/in/out which appears to be a unique feature of the 'smart enema' machine. Otherwise an intriguing and cheap option.
My second idea was this:

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a 12V DC solenoid valve
Very similar to the first idea, but without a built-in timer or power source. I've fitted similar things to these for their intended use (central heating) and they are smooth, quiet and reliable.
Again, the challenge is to convert from household pipe sized fittings to more appropriate enema sized tubes (unless you're really into big tubes?) and you would need to find a 12v DC supply (plentiful and cheap) plus a timer (also plenty and cheap). The advantages here are that by using your own timer you can add more cycles, down to a 1minute intervals, and 'build' your enema experience.
Also, if you have the skills, or can find a suitable remote way to power on/off, then the enema can be triggered 'on demand' (by you or a friend 😉 ) and it's also cheaper than the 'Smart enema' option, even with separately purchasing power supplies and timers.
As with my first alternative, this will not deliver the pump/vacuum 'in/out, in/out' experience of the smart enema machine.
Food for thought?
MJ