Re: A question for connoisseurs...
The toilet should have an air-gap between its cistern and the incoming water supply, to protect the rest of your house's outlets from cross-contamination. This is often a problem with the shower hoses that are fitted next to toilets - and because they're on a common water system, often on the floor above the kitchen sink, they're a serious backflow risk. Back-siphonage if dropped in the toilet bowl. You hope that the installer at least spends £5 on a double check valve, which is illegal but mostly effective. There's at least one WC sold in the UK that complies with the water regulations - I seem to recall they're about £6,000 though.
The nozzles are then recessed under the seat/rim, so that you don't pee on them or if you're really trying manage to balance a flying poo on them.
When you're finished they then pop out and wash your front and/or back - and then pop back away again, and have a self-cleaning thing. Don't know if they only clean with water, or have a bleach tank though. Plus optional air-dryers.
We designed a unit to retrofit for hoses for a large hotel, and comply with the regs. Got to have warm water on your bum too, so it's quite big with all the stuff you have to cram in the cabinet. But nobody wants a cold bum, however clean...