Korea
Korea - mini brain dump:
Korea has kissing booths, spas, and ktv. - kissing booths - described above - ktv - you go to ktv and get girl, you pay for time there and then go afterwards, depending on location you can pick girl or not - spas, these are similar to soaplands in japan, example maruspa.com or dioranma.com
These places are generally discoverable via Google OUTSIDE of Korea, or if you are in Korea via a VPN to outside of Korea. Inside Korea on a regular network it's harder as the government isn't exactly a fan of these places.
As far as servicing foreigners go: - in my limited experience, no issues were encountered as long as you were well dressed and groomed. - I speak almost no Korean other than hello or goodbye. - places do take walk-ins just fine, no appointment was needed
Other things: - US military: ditch the uniform, and anything that stands out - grooming, reminder on this, they care about fingernail cleanliness etc - credit cards worked at most places