Musical notes

{This was for the contest. . but it's not quite "dirty" its more just a lot of puns with a hinting at more. . please tell me if it doesn't qualify so i can add that so ppl don't waste votes}

I once was playing music
In a concert hall in Munich.
And after all the show was done
The harpist showed up with his son.
"You're music sucked from what I heard."
I told him "Now, that's quite absurd."
Then I explained my music grand
And all my notes within the band.
"Without this note it would B flat,
I'm sure that you can both C that.
And with this note here I F things up
Without it things get quite abrupt.
And over here, It would B sharp
That's something you can't do on harp"
"G" he said before he left
"Just one more thing, please drop the F"