Why I Never Date Girls who can Spell Penicillin

 
In my youth I roamed streets of iniquity,
 Most generally, travelling by night;
 My temperament being the dicey sort
 That preferred to avoid the light.

 Whilst embarked on one shady excursion,
 I espied a passable wench
 Whom I took to be just the ticket for
 Certain appetites I sought to quench.

 Importuning a dubious citizen,
 I asked how to best track my game.
 He said, looking at her, "That's Osfa".
 I remarked. "What a curious name."

 He sneered, "It ain't a name, greenhorn.
 You don't want no part of that haul.
 Osfa's an abbreviation—
It stands for, One Size Fits All."