At some point after like the 2nd or 3rd boss? If you talk to the male in the starting town bar (out of the 3 tables, he's on the top left table) he will mention something, and you can go to the blowjob prostitution place that is the area with the old ragged looking hobo in the port area (one map right, and 1 map south of beginning area).
I am unsure how I did it, but I lost the same that ahd it, after beating the "mountain bandits" you can possibly get from the guy on the right side "jobs counter" may give you a quest to go to the big house (first house on your left when you enter port area).
You need to do a lot of random talking to NPC's there, to get the otaku to do events with your character (he does hypnosis, also you may get the maid costume here, but I lost the same at some point).
At this point, you can also initiate the 2nd part of the prostitution events by talking to the brown robed guy in the first prostitution area, he tells you to go to the building to the left of the bar in the port area.
After doing a few prostitution and near 700 ecchi points, the head lady there will give you a job to go in a swimsuit/naked out at night to advertise the place. She also gives you a job at some point to go the first part of town north of the prostitution area inn to have some guy on the 2nd floor (talk to inn owner -> lady in kitchen -> man 2nd floor)
Once you do it enough to be able to walk around in bra+panties, go look for the guy at the bottom left of town (while in bra+panties) he will disappear when talked too, go to the bar in port, and talk to him again to strip in the bar.
By this point you can probably go full naked around town, talk to male NPC's to have a sex scene all over the place.
If you go past the south guard in the first town (can only do so after having sex with him naked) if you talk to the 4 hobo's , you get a GoR ending (SAVE BEFORE YOU GO IN)
