That's the old classic, "The Lady in Red."

Let Her Sleep Under the Bar
(The Lady in Red)

'Twas a cold winter's evening, the guests were all leaving,
O'Leary was closing the bar,
When he turned and he said to the lady in red,
"Get out! You can't stay where you are!"
She shed a sad tear in her bucket of beer
as she thought of the cold night ahead,
When a gentleman dapper stepped out of the (phone booth)
and these are the words that he said:

"Her mother never told her the things a young girl should know.
About the ways of college men, and how they come and go, (mostly....go).
Now age has taken her beauty, and sin has left its sad scar;
So remember your mothers and sisters, boys, and let her sleep under the bar." ^^

Note from Joe Offer: This exact version is on page 64 of the 1958 printing of Song Fest, by Dick and Beth Best.