I'd say from experience that you should never have unprotected sex with people that you are not exclusive with and still that is not enough in this age and time. HPV and herpes certainly is in Japan. Lots of J females carry herpes and others have HPV. They get it from their parents, friends, and from hook ups. One can only imagine that a percentage of these women work in the sex business.
From blow jobs, oral sex, and penetrative sex, one should keep it covered! You can also get throat cancer. Throat cancer has to be one of the worst things to get besides women that get cervical cancer from HPV. Hep C is another disease passed on during sex and Hep C has been found to be present in the sex worker population along with syphilis and gonorrhea. Let's face it folks, safer sex is the best way to play! I might have played a bit loose, but I never got anything other than a warning from my immune system.
So while it is unlikely to acquire an STD, it certainly can be done. And Japan usually is where the resistant strains start. Many woman here are doing unprotected sex with many different men. The doctors don't test them properly and the women have no idea they have certain STDs as there are no signs. It could take HIV 10 to 20 years to progress to AIDS. Most with gonorrhea, chlamydia, Herpes, Hep C, don't even know they have it. And while I only know of one that agency that routinely requires STI testing, the other agencies lie about testing. Thus one could say that after a worker admits to not being tested since working for said agency(ies), I ban them. If they say they don't get their blood tested, same response.
I'd say that luck runs out and sooner or later, due to the lack of control of who is fucking who, who is tested and who is not, and other factors, it is unwise to have unprotected sex in Japan.
Straight man to lady boy---staight man to wife-----wife to wife's secret girlfriend---secret girlfriend to boyfriend---- boyfriend joins a gangbang--gangbang members of various sexual orientations--boyfriend meets sex worker shoots heroine (unknowingly)---Straight man/bisexual man infected---meets same sex worker---Sex worker gets infected and has unprotected sex with hundreds, thousands of men for various reasons. Infections skyrocket. Bad cycle or depiction, but female sex workers just fucking straight men that don't engage in risky business never get much more than a cold or the flu.
The problem is that people get infected because there is no way to control the players. Condoms can only protect so much but the best protection would be to eliminate crossover sex. Gays and bisexual men are the biggest threat to exposing others to HIV, HPV, and Herpes. Straight men pick up stuff from bar rats, coworkers, being cheap and trolling homeless areas, and sex tourism in 3rd world countries! The dangers are so great now that mongering of any type is actually suicide.
Morning warm up before I go out and enjoy the day!
I am now a celibate man. I vow never to be a playboy again.