I used to think that, with sex, anything goes.
I don't believe intimacy is possible with strangers. One might feel one has known people forever, but, unless one has known them forever, one hasn't known them forever. The feeling is an illusion. The feeling of intimacy that can arise from physical contact with such a person, or any relatively unknown person, is an extension of this illusion. Nothing is really happening. People's bodies are really not so different from each other. The specialness of this body or of some part thereof is in the mind; it is not a reality. The intimacy is not with the person but with the flattering idea that this specialness has given itself to you. The resultant exultation is self-worship, not worship of the other.
The intimacy is with a pre-existing idea of the person, or of an archetype, of which that person appears to be a token or instantiation, at least for now; the intimacy is not with the person.
Bodies do not connect. Minds connect.