Toto Washlet Electronic Bidet Seat

Bidets strike me as the type of thing most dads would adore but never dare buy for themselves. In case you anticipate that would be the case for your dad, this is as good as not-built-in options get.

It features warm water cleansing. oscillating or pulsating stream options, automatic self-cleaning of the wand and bowl before and after each use, heated soft close seat with five temperature settings, a warm air dryer (!!), an illuminating night light, and an air deodorizer for enhanced user experience.

You'll probably save enough on toilet paper in a year or two to cover the cost.