I hear Potter has a very special broom.

That's just one explanation, although one can't dismiss the likeness between a broomstick and a penis.

so youre saying i should be a devil for halloween and talk to witches?

It is funnier when you consider that they recalled a Harry Potter broomstick toy because it had sounds and vibrations. Given the thought most adults will come to when considering a vibrating stick made to go between the legs…. There was quite a media controversy over what was basically called a vibrator marketed as a kids toy at the time.
So I will for this time not go in to a historical frenzy of factoids and fact checking and instead leave it at:
There is certainly room to consider the broomstick as an anatomic stand in.