brain-wanking 

Act of spending one's time with very complicated theoretical problems which, when solved, do not serve for anything useful or practical.

J: Did you understand the sense of the problem in theoretical quantum mechanics which we solved in our course today?
P: It was just some brain-wanking. It does not have any practical meaning.

brain-wanking by xxteapot November 30, 2011

Walking the Brain

To pull your ballsack out of your fly and then zip to a suitable point as to which the sack becomes taut; the balls assuming the shape of the two sides of the brain whilst veins serve to add to the realism of the shape.

The ultimate purpose of such a maneuver being to offend when engaging in light conversation with others, subsequently enjoying the outrage when they discover the brain, whilst throughout experiencing the gentle caress of a light breeze on the sack.

Essentially a ball walk but requiring more art to pull off effectively and comfortably yet yielding a much more comical and appropriate name.

Jonny enjoyed walking the brain on a spring day, he was surprised just how long it took some people to notice his nuts were out during his strolls.

Walking the Brain by JonnyPye November 13, 2009

brainwanking 

Any intellectual/academic discussion meant more to show off the intelligence of the speaker than to prove a point or educate anyone listening.

Freudian literary criticism is pretty useless, to be honest; eventually they stop talking about literature entirely, in favor of pointless brainwanking.

brainwanking by kiefda03 June 10, 2010