Interesting the copy TOTO used to first introduce the washlet in 1980, the translations is essentially:

Everyone washes their dirty hands with water.  Nobody wipes it with paper like this.  Why is that?  You bottom is the same.  Your bottom wants to be washed.

This then unusual product caught on pretty quickly in Japan and now 70% of the toilets in Japanese homes are washlets.  It still hasn’t quite caught on in the US, by TOTO is trying with this campaign.