End up consuming second small Manhattan cocktail (6)

I haven't cracked this one yet — but the brilliant team at Times for the Times have:

AIM (end) reversed [up] containing [consuming] MO (second) + S (small). Orange juice and sparkling wine are the main constituents, very similar to a Buck’s Fizz. It seems to have originated at The Ritz in Paris c1925 and Bucks Fizz in London c1921 so I am at a loss as to what Manhattan is doing here, but perhaps one of our American correspondents can shed light?.