[It so happens, I read this in my devotions, today. I think I'll put this right here...]
The Christian idea of marriage is based on Christ's words that a man and wife are to be regarded as a single organism - for that is what the words 'one flesh' would be in modern English. And the Christians believe that when He said this He was not expressing a sentiment but stating a fact - just as one is stating a fact when one says that a lock and its key are one mechanism, or that a violin and a bow are one musical instrument. The inventor of the human machine was telling us that its two halves, the male and the female, were made to be combined together in pairs, not simply on the sexual level, but totally combined. The monstrosity of sexual intercourse outside marriage is that those who indulge in it are trying to isolate one kind of union (the sexual) from all the other kinds of union which were intended to go along with it and make up the total union. The Christian attitude doesn't mean that there is anything wrong about sexual pleasure, any more than about the pleasure of breathing. It means that you mustn't isolate that pleasure and try to get it by itself, any more than you ought to try and get the pleasures of taste without swallowing and digesting, by chewing things and spitting them out again.
C.S. Lewis from "Mere Christianity"
A problem with Lewis' quote (and biblical study) is that there are two passages where Paul quotes Genesis 2:24. Ephesians 5:31 is within the context of marriage (and Christ and the church).
In 1 Corinthians 6:16 it is in the context of having sex with a prostitute. Whether married or not, sexual intercourse (according to Paul) causes the two to become one flesh.
Actually people who taste for a living, e.g., wine tasters - do taste and spit it out.
I admit I'm having a hard time knowing if your intent is to make a case against Lewis' argument in order to say casual sex is not that big a deal, or are you highlighting the way Paul quotes from Genesis to say something else? Forgive me for just backtracking and spelling out how I read the quote and how it relates to Paul's teaching.
The point of the Lewis quote (which I find very helpful) is that we should not separate the one kind of union from the others that are meant to go with it. I think a good example of this is when you see an older couple who have been together many years knowing each other thoughts and able to complete each other's sentences. I take that as evidence that the union God intended in marriage is meant to go much deeper than just the physical union.
I don't think your quotes from Paul's letters directly contradict that argument. Paul's point in 1 Corinthians is to avoid sex with prostitutes for the same reasons - don't try to isolate the physical union from the other kinds of union that are meant to go with it. The point in the other writings is that God established marriage to be a special union between a man and a woman. I think all this lines up with "Mere Christianity" very well.
I also think your illustration of wine tasting is perfectly aligned with Lewis' point. Wine is meant to be fully enjoyed on levels beyond just taste, something that tasters cannot do while on the job. This may even be a great illustration to use in Bible class. Would you prefer to just taste the wine and spit it out, or do you want to sit down and enjoy it, maybe with a wonderful diner, good company and a relaxing atmosphere? If all you want to do is spit, you will never fully understand or enjoy what that wine was meant to be.