I figured out how to go the free sex mode. The site is in Japanese but it may help you out:
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Download the 2 attachments on page 3 on this forum first and make sure you have the full version of the game and not the demo. You can get to the free sex mode on the demo mode but you can only access one function. Downloading the 2 attachements you should be able to get all the functions for the free sex mode. Now you can access all the cgs and the ending, but it is important that you start a new game. Do
not continue on file20 if you want to get to the free sex mode.
Follow the five steps below:
1. Go the Beginner's dungeon.
Make sure you level up and get enough money to buy equipment and get strong enough to face the boss. Go to the water fall first and that room to the east area of the cave. Then you got to go back to the waterfall and then go that room or the next event cant be triggered. You get to go to the hidden area and then get to the crystal. After getting the crystal you got to defeat the boss. You cannot open the gate yet. After doing so you can learn the cross guard formation from the old man in the entrance of the dungeon. Go back to the guild.
2. New mission "save the kid by going to the western dungeon".
There should be a new dungeon right next to the beginner's dungeon. It should be easy to go through but make sure to equip your party well and make them learn some magic in town before going in. Beat the boss and save the kid.
3. Go back to the guild and then go back to the beginner's dungeon again.
Go back to the guild and talk to the girl and she will make that crystal into a card. Go back to the locked gate in the beginner's dungeon and use that card to open it. Go inside and you go to the deepest part of the cave and you should find an area with 5 pillar. Check the pillar in the middle and you should get a moon shape thing which is supposed to be a key.
4. Go back to the guild and she will tell you to talk to "Granma" living north west to the town.
After talking to her in the guild go the world map and you should see Granma's house. She will talk to you about an abandoned temple. Go the world map and you should see a temple to the east.
5. The abandoned temple
Make sure you press the 3 buttons so you can access the stair case. You jump over steps by pressing enter. Then you should reach this area where you use the moon shaped key. Bathe in that water and a dragon will talk to you. Go back to Granma's house to report this.
6. Go back to town and now there's the TAB function
You can use the tab function to travel alone. Go head home to your room and go the room inside your room and there you go. Finally you get the free sex mode.