Yoshiwara Etiquette I Think You Really Need to Know
Short answer: be on time, be respectful, no secret filming, no pressure; shops can turn away anyone drunk or breaking rules. Treating her as an equal matters more than memorizing a list of "tricks".

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Short answer: the baseline is just a few things — arrive on time, follow the staff, no secret photos, recordings or violence, and don't push for anything she doesn't want.
Use a normal name for your booking — staff may call it out in front of others. In the waiting room, confirm your companion and payment as instructed, and don't wander into the back.
If there's a language barrier, use a translation app; companions who are polite and proactive are usually easier to communicate with. Not speaking Japanese is no excuse for crossing lines.
When time's up, it's over — don't pester to extend in a way that makes things awkward; if you want more time, ask the staff through the proper route.
Under-18s can't go. Shops have the right to refuse anyone who is unwell or clearly drunk. These rules are for everyone's safety, not to scare you.
Related: My First Time in Yoshiwara: From Booking to Leaving · FAQ