A handjob while playing the banjo.
There once was a boy on a train
Who pondered the source of his pain
He desired a handjo
But misplaced his banjo
And so his dreams went down the drain
An unsatisfactorily-administered handjob that does not result in an orgasm, as it does not arrive at completion.
That girl thought she was doing me a favor, but she really only gave me a handjo.