"Top-tier soapland in Kawagoe" — soapland being the licensed full-service bath-style format. Some people hear that and immediately get it; others don't.
I'm forty-two and still walking the floor of this world, so I'll lay it out from a real-world angle.
Why this topic matters
Information about fuzoku is surprisingly disorganized. Beginners especially tend to end up stuck, not even sure where to start looking.
What it comes down to, concretely
In a word: whether you know it or not changes the quality of the experience.
What I've written here is the essence of twenty years of accumulated knowledge.
Last word
If you've got questions on this topic, hit me in the comments or on social. And check out First Class Ruby while you're at it.