I was always told that sleeping with the "Greek King's daughter' was a promise of significant and uninhibited sexual fulfilment. Though the precise words used to describe it to me were more explicit.

By the way, the requested Limerick by James Joyce about Lady Gregory goes:
There was an old lady named Gregory
Who cried, "Come, all ye poets in beggary."
She found her imprudence
when hundreds of students
Cried, "We're in that noble category."