Yay, more Reth fans!
The game should currently end when you sleep in your room on the second day. It should bring you to the afterword where the dev is talking.
In order to see the new Reth content you'll need to have low charisma and lie to Silas. You'll know you're on the right track if he doesn't offer you a ride and you meet Aldric. From there, some of your choices involving Reth will allow you to have more or less of the new content with him.
I plan to have all the characters be able to top or bottom depending on player choices and also possibly have a toggle option where the player just get's asked which they would like (if I can figure out the coding for that), but those kinds of scenes are a long way away.
Also, I appreciate the offer. I do hope to someday be able to have the game translated by teams of volunteers. I will definitely keep you in mind. Thanks!