In the popular viral rap video, Harry Potter in the Hood, the lead, dressed as Potter, refers to himself several times as H. Piddy.
"He's a magic man, he puts the hex in the city
Don't call him Harry Potter
Cuz my name is H. Piddy"
Many young people now use the term when referencing not only the rapper's character in the music video but the character of Harry Potter as well.
Tonight I'm going to make some hot cocoa and read me some H. Piddy.