In the comments for the story, there are several requests for a sequel or more chapters. I don’t have any plans to do one, but I thought I’d share some thoughts on what I could write.
Dylan, Emily and Alex have to make a number of decisions right away. One would be how will Dylan and Emily interact now that they are lovers. I’d say that they would decide that Dylan and Emily should try to act as normal brother and sister except when they are alone with Alex. I would say that Alex’s goal (and Dylan will go along with this) is to prepare Emily to re-enter the dating world when she goes off to college. A corollary to that is that Emily and Dylan plan to have sex only this summer. There could be some struggles with that, temptations, regret over giving his sister up, etc.
The next decision is who to tell that Dylan and Alex are an item. I’d have them keep it a secret. Definitely not tell Dylan’s parents as he is grounded and having his girlfriend come over every day isn’t compatible with that. After the grounding is over, it would probably still be in everyone’s interest to not let Dylan’s parents know that they are dating as his parents wouldn’t be happy with Alex coming over every day unsupervised if she was Dylan’s girlfriend. Also, I think people would be more understanding of Alex and Emily spending time alone if they didn’t know that Dylan and Alex were an item. Plus Dylan and Alex love to flirt and flirting works best if you aren’t know to be an item.
With all the said, the only way for an new chapter to be interesting to people is if someone else gets involved. The obvious suspect is Dakota. So the next day, Alex, Dakota and Faith come over; Faith leaves; everyone else has sex.
Now that problem with that is that it really breaks the logic of the story. The first day is all about Alex, Emily and Dylan showing their love for each other. If Dakota gets added in, then the story becomes about having hot sex.
Looking a little longer term, extending the story is going to hit the problem that the relationship will end when everyone goes off to college. Alex is going to a different college than Emily (and probably Dylan) and she’ll want to focus on her studies full-time. If Emily is healed by the end of the summer, she’ll want to date.
I have thought long-term about the set up and I have this elaborate story in my head that takes Alex, Emily and Dylan to middle age. Alex becomes a world-renowned eye surgeon. Emily becomes a manufacturers rep for companies that sell to dentists. She has no interest in having a serious romantic relationship, so enjoys having sex with Dylan when Alex is too busy (which is most of the time). Faith turns out to have been Alex’s first female lover and is gay, though she marries Elijah anyway. Elijah is killed by cops in one of those cops-mistook-unarmed-man-to-be-armed shootings. She winds up marrying Dylan and having two kids with him. Alex, Emily, Faith and Dylan live happily in a big home together. It’s a rambling story without any climactic sex scenes that make good erotica so I’ll never take the time to write it down, but I’ve enjoyed thinking about it.