Agree with the quoted post... asking for extra drink service in Y has the potential to be very awkward and is really something I'd just prefer to avoid. I hate feeling like I'm being judged for drinking, and you certainly run the risk of that in this scenario.

BTW, trust me, I get it... if it's not an early morning flight and/or I don't have any work that needs to be done immediately, I tend to have a few drinks, particularly on relatively longer services like transcon flights. I would find it very awkward if I had to track down an FA for extra alcoholic drinks in Y... particularly if I got the sense that I was being judged with the look that says, "Oh, you want ANOTHER drink?" And there's one more level to the awkwardness if you're actually DENIED when you make the request, as another poster reported above.
While this can theoretically happen in F also, experience suggests it is much less likely to happen up front, so I find that getting into F, however that can be accomplished (miles, elite status, or simply paying the cash) can potentially save all this awkwardness.

And if F isn't practical on a given trip for whatever reason, maybe consider having an extra pre-flight drink or two (lounge, airport bar, etc.) to keep your blood alcohol level a bit higher so you won't need to drink as much during the flight to achieve the same level of relaxation.

Just my two cents - I know everyone has a different tolerance (pun intended) for awkwardness dealing with FAs.