Not being funny, but I don't really understand why you would want to do this It is not natural behaviour for a cat, and there is a risk they could fall in the toilet and get soaked

It is different if a cat opts to use the human toilet of their own accord. I had a friend years ago whose cat did this, but there were also times when the cat chose to use an ordinary litter tray instead, so my friend always provided a litter tray.

Tbh I doubt it is at all possible anyway to train a cat to use the human toilet, they do it of their own accord from watching humans and copying them - if they are so inclined.

 

Personally I feel its the same as those who want their cats to go outside all the time (even in the depths of winter) - to me, litter trays are part & parcel of having a cat and on that basis I really dont get why some people seem to have such an issue with them

Litter trays don't have to smell (at all!) If the cat is fed a decent diet and the tray is regularly attended to

Using a toilet without any litter to dig around in / bury in is totally unnatural to cats

 

The main reason I've heard given for wanting to is avoiding smelly litter trays and how it's not a pretty sight for visitors. I shouldn't think it's a very appetising sight for a visitor or indeed yourself to find little floaters when you go to use your own toilet. Still, each to their own.

Have a search on You-tube, there are lots of tutorial videos if you're really into the idea but I'd agree there should always be a litter tray. What if a visitor left the lid down and you didn't realise? And unless you teach the to flush, you're going to find the toilet a lot harder to keep clean. More bleach, worse if the cat falls in. A litter tray changed daily is perfectly clean.

 

I trained 3 of my cats years ago, using the Litter Kwitter. They all learnt really fast and had no problems or accidents. I did it for fun, always prepared to go back to trays if the cats objected to training.

I went back to trays when I got breeding cats, if I leave the toilet seat up they'll still use it. I had no issues keeping the toilet clean, a simple flush when I came in from work or through the day, just like scooping a litter tray really.

I lent my LK to someone else, her Bengal was fine, the Ragdoll refused to use the toilet at all, even with the early stage disks.