When a couple return from a first date together, typically, the man will ask the woman, "Do you want to come up for a coffee?" This, of course, is the traditional euphemism for "Do you want to come in for a shag?" There are usually only two possible responses: either (a) "Yes, I'd like to" (ie "I'm gagging for it.") or (b) "Thanks, but it's a bit late, and I'd better be getting back." (ie "I wouldn't let your dick within 50 miles of me.") In both instances, the need to maintain propriety severely restricts the information that can be conveyed, thus leading to possible confusion and/or offence.

In my opinion, therefore, men who buy coffee should first be required by law to declare how good they are in bed. Their points-out-of-ten rating would then determine exactly which variety they'd be allowed to purchase. Eight out of 10 or higher, for example, would give them
carte blanche to choose from anything in the shop. Six or 7 out of 10, and they'd be allowed everything but the prestige beans. A score of 5, however, would restrict them to the milder Colombian and Kenyan blends. Anything lower, and they descend into decaffeinated territory and worse. One or 2 out of ten - the premature ejaculators and their ilk - would, appropriately, only be allowed to buy instant coffee.
When you think about it, the reasons behind this should be obvious.
If my policy were to be implemented, the usual to-shag-or-not-to-shag exchange would take on much greater significance, while still remaining within the boundaries of good taste and manners. For instance, the question, "Do you want to come up for a Kwik Save Economy powdered coffee drink?" could be answered with a polite, "No, thank you. I only drink freshly ground Jamaica Supreme." Similarly, someone asking, "Do you want to come up for some Kenko Original? It's indistinguishable from real coffee. I swear to God. I'm begging you to believe me. Please, please, please!", could be responded to with a friendly, "I'm sorry, but I wouldn't drink that WEAK, WISHY-WASHY PISS if you paid me. One gulp, and in a second, it's gone."
On the other hand, “Do you want to come up for a cup or two of Whittard’s Caribbean Mountain?” would undoubtedly bring forth the answer, “God, yes! Oh God! Yes, yes, yes ….. Yeesssssss!”
As you can see, the man is able to convey, not just the fact that he wants a shag, but the exactly quality of the shag that's on offer. For her part, the woman, should she so wish, is able to decline with good grace, explaining
exactly why she isn't interested in that shag, yet without giving offence. It's the coffee that she's turning down, not the person.
I suppose in some circumstances, it's conceivable that the coffee could be so good as to surpass the actual sex itself. There are a couple of Jamaican and South American blends that come to mind. The only drawback here, though, would be if the woman accepted the man's invitation to go up for a coffee, drank a cup, had multiple orgasms as a result, and thereafter didn't want any sex. But this needn't be a bad thing. Indeed, a man who got a reputation for giving good coffee would soon be the envy of all others. It would probably push up the price of cafetières, though.