Bitching Post

The person who you always Bitch to ( not Bitch about)

Could also be refered to as your bitching pal/buddy. He/she probably doesnt care what your saying, but just listens. ( occasionaly joins in)

Tom: Argh, Tim is so annoying!
Luke: Yeah...
Tom: Sorry for being your Bitching Post by the way.
Luke: It's alright man...I don't like him anyway.