When your boner takes over thinking for your brain. Similar to the Blood-Brain Barrier where only certain substances can pass through to the brain. The Boner-Brain Barrier doesn't allow any thoughts to be processed from the brain since they are all processed from the highly sophisticated thinking center of the penis. This can result in making illogical decisions and having regrettable sexual experiences.
Hey, why'd you make-love to that 350lb manatee last night.

Three words, man... "Boner-Brain Barrier"
by The definer2017 January 19, 2012
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