The Japanese have been into porn, especially BDSM, long before it was ever popular here in the U.S. You can find Japanese porno in the era of the Meiji; there are entire museums dedicated to old paintings of Japanese masters depicting women being tied up (BDSM stuff) that are thousands of years old.
The trend toward large-volume enemas is an alarming one: you only have to read to read some of the posts on this web site to see a growing "competition" of people claiming to take retention enemas of 4-5-6 qts or more: people have absolutely no idea of how dangerous, possibly fatal, the trend is, particularly in people relatively new to enemas. What we are not reading on this web site is the number of people who have died from toxic shock when their colon had burst much like a water balloon, in a number of cases from a undiagnosed polyp that weakened the intestinal wall. They will not be dissuaded from their folly. (Reading some of the recommendations for the use of enemas is further proof of that folly: I hope that it will not cost the life of an innocent trusting some over-exuberant person who didn't know the risks associated with their behaviors.) I wonder if their defense will stand up to a charge of voluntary manslaughter.
The use of Fleet products is also coming under fire in class-action lawsuits. Most recently, the Fleet Phosphate Soda laxatives are now the object of a class-action suit, and now it appears that the regular Fleet enemas are also thought to be medically suspect, though possibly from over-use). Many of the preparations used to cleanse the colon prior to colonoscopies are also the object of class-action lawsuits. Two different law firms associated with such lawsuits are currently investigating a mini-enema product that contains benzocaine, now thought to produce a powerful carcinogen when the benzocaine breaks down.
Before people embark on taking the advice offered by others on this site, I recommend that they would use common sense, read medical texts and where the use of an enema is not recommended, I think that they should refrain from conducting medical research on their own.