I think it's a interesting idea what you propose about Sam and what happens next at Cathy's.
The only issue is that Sam's event is optional while Cathy's happens no matter the previous choices. So I don't see what happens with Sam being the trigger for Sophia's decision of accepting the swinger proposition (assuming there will be one!). In case, it could be in the form of an optional Sophia inner thought that confirm even more her idea of accepting. But I don't think she will accept just because of what happens with Sam (dunno if it was also what you had in mind)
Getting back to the after concert, I think that is most likely that either the event happens in the car or if there is a round 2 it would be just after, like
nexer said while she is waiting for Liam.
It's difficult to see it happening after Cathy's event. Why, how and where should they meet again? One possibility could be that in the car Sam again starts with his romantic talk with the "longing" feelings but this time Sophia gently but firmly turns him down (no choice for the player though). So it ends on a quite sad note for him.
Then they can meet again after Cathy's event because e.g. Sam texts her a sobby apology (dunno if they have each other numbers though) or she spots him sulking somewhere once back. And then event starts again with Sophia trying to comfort/ reassure him and one thing leads to another.
Where? well, let's forget the treehouse for a moment (we teased
GingerSweetGirl enough
) only the patio and the back of the pool seems to be safe spaces for some action out of sight as nexer pointed out.
I don't know, if we have to explore all the possible scenarios this is the genre of story line I could come up, maybe you have better ideas. I still find that the car or while waiting is more likely to happen.
