My 3 month old German Shepherd puppy is humping pillows

by Todd
(Georgia, USA)

I have a three month old male shepherd who will start chewing on a pillow then while he is still chewing it he will start humping it like crazy.

I read that dogs don't go through puberty until about 6 months or later and was wondering if this is normal behavior for a dog of his age and if I should discourage it by removing the pillow. Also, as a side note he is not neutered.