In simpler language - after you wipe your ass, you sit down on the bidet, open the faucet and gently rinse your butt.
At this stage, your butt doesn't contain large pieces of shit, it's in the same state when you take a shower.
As a consequence of using a bidet, your underware stays clean, no more 'thin brown line' on white underpants, no shitty smell and no creamy feeling in the butt when you sweat.
http://www.ncbi.nlm.nih.gov/pubmed/16033465
> Many individuals may be unaware of the risk of air-borne dissemination of microbes when flushing the toilet and the consequent surface contamination that may spread infection within the household, via direct surface-to-hand-to mouth contact. Some enteric viruses could persist in the air after toilet flushing and infection may be acquired after inhalation and swallowing.
EDIT: there's no need to downvote...I was simply asking a question, as I've never used a bidet. However in my experience, it's not possible to remove all the poop simply using a shower...soap and hand action is also required. I'm curious about how the spray can clean you properly.
You can wash yourself with soap, and then wash your hands (which you should do in any case). I don't see how you can think that leaving all that the TP doesn't take away can be _more_ sanitary than a bidet.
I think if you really want to get clean after a particularly messy poop, the best way is to have a shower from the crotch down.
The whole bidet thing just seems messy and unsanitary. I'm sure that there's a way to use it which isn't messy and unsanitary, but I'm not about to make a mess trying to learn!