I finished writing the introduction and the "couch route". While the latter is definitely going to be the shortest path, I decided on a goal for this game, which will be to try to make every path rewarding and not end too quickly, regardless of the player's choices. So this concerns the "couch route" and the "stop" paths in particular, with the latter being the biggest challenge, as I still want to offer the player some content and choices after they choose to interrupt the sex scene. We'll see how feasible this is though, let's say this is an ideal I'm aiming for.
I've also started Chris route, and I added a choice in the introduction allowing the player to set the relationship between Zakia and Sue as non-sexual entirely and from the beginning of it. This alters a few sentences down the line, and remove the choices leading to the sex scene if the corresponding option was selected.
Finally, I've removed purple links (which show up when directing to a node the player has already visited), because I find them ugly in Twine and I generally want to decide how much awareness the player is given on how they are navigating the game with my own code. I looked up how to do this for my last game and I'm probably going to continue using it. For anyone else who wants to get rid of purple links (without changing anything else about the default appearance of links), all you have to do is to copy-paste this into the "style spreadsheet" in the menu of your Twine story.