All right, I must definitely not say anything to S, because the best way to communicate what I want to communicate is to say nothing. However I do like S and we have done all sorts of interesting things together at various points over the past twelve years.
I am also vulnerable to being convinced that it was I who got overly skittish in this instance. That is why I am worried I could fall into S’ trap again, even while I am still angry about the most recent one. I need quinine, if not a vaccine, against this eventuality.
So perhaps I am rehearsing speeches for when and if S does reappear and want to reestablish our friendship in some way. Knowing him, he will do that with some interesting bait like a very tantalizing invitation I am unlikely to get from anyone else. So, let us rehearse this, as a speech to have in mind for myself anytime I might need it — so that I will remember what my own position is and remember that I am right.
I appreciate the kind offer. But it resembles offers you have made before, when you have tried to manipulate me into uncomfortable situations — including situations I had already stated I did not like or would not like. This car/airport incident was the most severe, and it really gave me pause.
I was 7,000 kilometers away. Your proposal went directly counter to all of the wishes and priorities I had expressed before leaving. Note that I never asked you to be involved in my trip. Once you offered, I asked repeatedly whether you were truly comfortable with the plan, because I did not want it changed.
You also know that I am not interested in intimate situations with you, even the tepid one of merely sharing a motel room. You know how uncomfortable I am to be asked. Trying to set such a situation up again, especially in the context of the car/airport pickup arrangement we had made, really crossed a line.
That is why I do not trust and am not accepting the present invitation.
Axé.
coldhearted scientist وداد 
Another bad letter.
Rather:
Dear S
Our friendship is just as it was before, which is to say I am not planning to have sex with you. I’m not sure if that was your idea with the motel room, but anyway this is just to let you know!
I am very happy that we can share quality time together, but, what were you thinking!!
You had to be nuts!!!
Anyway, I hope we can get along together and have some good times, but I’m just not interested in that kind of a good time, and I think at this stage in our relationship, you ought to have got my drift.
Anyway, Brazil blah blah blah.
Hahaha, so I really *am* a bad communicator! I am infinitely too subtle and serious!
OK, I’ll lighten up. This will give me power since it will mean lightening up on myself as well.
And I *will* change the relationship, along the lines of my subtle ponderings, but I will not announce it to him — I’ll just do it.