Last year, Bennett Friedman, who owns a plumbing showroom in Manhattan called AF New York, took a business trip to Milan. On the morning of his return he faced a choice: stop in the bathroom there or wait until he got home. The flight was nine hours. He waited.

The move seems almost masochistic. But in his home and office bathrooms, Mr. Friedman had installed a Toto washlet. To sit upon a standard commode, he said, would be like “going back to the Stone Age.”

“It feels very uncivilized,” he said.

For those who own Japanese toilets, there is a cultish devotion. They boast heated seats, a bidet function for a rear cleanse and an air-purifying system that deodorizes during use. The need for toilet paper is virtually eliminated (there is an air dryer) and “you left the lid up” squabbles need never take place (the seat lifts and closes automatically in many models).

Jean Z. Poh, founder of the luxury jewelry e-commerce site Swoonery.com, said a washlet is, in its own way, a luxury item.