This is of the 'washlet' variety. After you 'go', you can press a button which then releases a nozzle which squirts warm water right where you need it! The first time is a bit disturbing - especially when you don't realise you also need to hit the 'stop' button when you've had enough! - Just think of all the paper that can be saved!
- These toilets are more common in Japan than you think they'll be - even Youth Hostels have them!