Based on the oft-quoted minimum-socially-acceptable-age-of-a-partner formula, which is half your age plus 7 years, I have provided, below, a table of said ages.
So, when you’re out and about with your favorite WL, if she is below the tabulated age you should introduce her as your “niece”. For example: ‘Yes, waiter, I’ll have a Knee Trembler with a twist of lemon and my “niece” will have a Champagne Cosmopolitan.’
If your consort is over the acceptable age, hold your head high and proceed with confidence knowing that your pairing is within society’s acceptable age range. You can, therefore, boldly introduce her as your “fuck buddy extraordinaire” knowing that there is no social stigma attached to your tryst whatsoever!
You will note that I have cut the age range off at the legal drinking age of 18. This is clearly because you shouldn’t be buying drinks for your “niece” if she’s under the legal drinking age anyway!
And remember: fornicate responsibly.