This book is one I have yet to be able to splice together enough to locate, I was 10-12 (Currently 48) The issue is that I read so many books of similar genres, that the stories jumble in recollection, so I have found some of what I remember as a book, have been multiple story lines converging in my memory. This may have been one book, may have been books in a series. I cannot even begin to estimate the books I read over my life, but at that age 3- a week was normal and 2 or more at a time was as well.
As remember this story line... I believe there was a person traveling alternate realities, sort of like cloud atlas style, but a single timeline not a progression over millennia. It had sexual undertones in some areas, rather explicit in others. In one timeline he was an android, and he and a female (as androids can be I suppose) companion broke socially accepted norms or rules by exposing wires in their fingertips, that produced an intensely intimate and pleasurable experience when they touched them together (Implying some meta orgasm). This was something expressly forbidden. In another timeline his female companion was a human form unicorn. They were in a magical world, where he was learning how to harness magic. The unicorn "For some reason the name Leena comes to mind instantly when recalling" went into heat, and lest he lose her, he had to make sure she was properly mated so she did not have to follow instinct and leave to find a stallion of her kind. So he had to do so with the virility of a stallion (Since she was after all a horse/unicorn). When he fatigued he learned "magic" ways of making himself capable of mating again...
