Not long ago, a Japanese friend complained to me that he could not find a high-tech toilet while on holiday in Hawaii.
In fact, he admitted to being almost traumatised by the experience.
He was referring to those Made-in-Japan toilet seats that, after one is done relieving oneself, will gently wash one's bottom with a spray of warm water at just the right temperature, followed by gusts of warm air for the finishing touch.
The Japanese often refer to these high-tech toilet seats as "washlets" or "shower toilets", after the respective brand names of toilet equipment makers TOTO and LIXIR.
My friend, who is in his 30s, had probably always used such toilets ever since he was born.
They have been around as early as the 1970s and according to consumer trend surveys by the government, over 70 per cent of toilets in Japan these days are fitted with high-tech toilet seats.
They are found not only in private homes, but also in public buildings, shopping centres, and even in schools and some public toilets.
No wonder my friend had experienced considerable discomfort when he was forced to use toilets without the high-tech features he was used to.
But he is not alone.
According to a survey in March by market research firm Citation Japan, both Japanese men and women ranked toilet conditions as their greatest bugbear when travelling overseas.
Of those surveyed who regularly used high-tech toilets in their daily lives in Japan, nearly half - 46.8 per cent - said they felt truly inconvenienced when they are unable to find a high-tech toilet while abroad.
For such situations, TOTO has, since 2007, been selling what it calls a "portable washlet" that allows the user to replicate the spray of water in the privacy of a toilet cubicle.
Electronics maker Panasonic has been selling a rival product since a few years ago.
Such products are typically about the length of an outstretched palm and cost about 6,000 yen (S$74) each.
Besides overseas holidays, these gadgets are also in demand by people involved in outdoor activities such as camping and mountain climbing in Japan in places where high-tech toilets would no doubt be a rarity.
At first, older Japanese were the ones more likely to bring along such portable sprays with them on holiday.
But these days, the portable sprays have become more fashionable, coming in various colours.
Says spokesman Keiji Hata of Panasonic's Consumer Marketing Division: "We discovered that young people were become increasingly fastidious about personal hygiene. So we designed our product for young people, especially women."
Called the Handy Toilette, Panasonic's latest model has sold over 20,000 units since it went on sale last September.
Here's how it works.
The built-in tank is filled with water from the tap - or with warm water up to 40 deg C - and the nozzle then attached.
Aim the nozzle at the desired "spot" either from the front of the body or from the back.
Panasonic's model uses a smallish tank that can carry only 130 ml of water for a 20-second spray.
The latest version however allows users to attach a medium-sized plastic bottle - such as those used for mineral water - directly to the nozzle to give a longer and more satisfying wash.
But it is not just the lack of high-tech toilets, whether overseas or in rural Japan, that has spurred sales of these products.
Surveys have also found that more and more women in particular are becoming averse to the idea of using high-tech toilets in public bathrooms and prefer to bring along their own portable spray.
Since last autumn, both Panasonic and TOTO have reportedly been promoting sales of the portable sprays to tourists as well.
Panasonic's high-tech toilet seats are already a hit with Chinese tourists in particular. Sales of these seats at souvenir shops are outnumbered only by sales of sophisticated rice cookers.
Compared to high-tech toilet seats, which cost about 50,000 yen each, the portable sprays make a more affordable souvenir to bring home to relatives and friends.