I was 19-23 and in Europe/Asia on Uncle Sam's dime. I was also a naif at sex (one prior experience). I landed in Europe first, specifically Frankfurt, Germany, for a month before heading to my permanent duty station. Outside of the main train station in Frankfurt was the city's sex district, probably 2 or 3 city blocks square. I utilized it weekly, picking out a huge brothel that was only known as Crazy Sexy. You walked in via a parking garage into a huge, nearly barren room: to the right of the entrance was a bar, to the left was a series of arcade machine. Throughout the room were the main supporting concrete pillars for the building. The floor itself was concrete. The air was always thick with hash smoke, the walls lined mostly with young G.I.s. On the main floor were all the girls - Crazy Sexy advertised 300 women. I got it in my head that I would come once a week until I had been with all 300. Impossible and stupid, but that's what I tried.
The typical experience for me was enter, have a drink, catch a contact buzz and decide who appeared fetching to me that night. Once the woman agreed (had to be her choice; prostitution in Germany was legal and if the lady in question said no at any point you would meet the polizie) we went upstairs (3 stories) to her room. We undressed and the woman would wash me and inspect for and STIs - then the prophylactic went on - always.
I would guess it was never no longer than 15-20 minutes before you would start to hear the click click click of the German shepherds the bouncers walked up and down the hallways, your cue to finish up.
I went at least weekly, sometimes twice or three times a week, when I was not in the field. This held true for the 2 years I was in Europe.
Asia was the same only more relaxed. I think that's right. In Asia it was normal to go into a barber shop, on base, and receive an $8 haircut, with $2 more for a manicure, and an additional $5 for oral sex - all at the same time. There were at least 5 chairs filled at any time. Sex on the economy was similar to the Europe experience, except the 'foreplay' was different - there were more subtle patterns to the initial greetings and information exchange before the actual sex...
Individual experiences were always different, some slightly, some markedly, but the common denominator throughout was the absolute zero tolerance of violence toward any of the women - it was worth your life in some places. Conversely, I heard about places - especially while in Asia - that not only countenanced violence, but offered it a la carte.