When you are doing something that makes sound and you don't want other people to know you are doing that activity. So you try to cover up the noise you make with another thing that makes noise.
When you poop you turn the bathroom fan on to create a sound barrier.

When you masturbate and other people are in the house you turn the T.V. louder.

When having sex you turn on the T.V. or music.
by killacab February 19, 2012
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The distance from the sound of your maturbation to the point where people could hear it.
My door is weak and wooden, so my Sound Barrier is pretty weak.. Makes jacking off with a fleshlight a chore..
by Douchebag82 December 12, 2011
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The act of inserting one's penis into someone's ear. Also referred to as ear-sex.
"Dude, last night I almost got caught while I was breaking the sound barrier with Alex!"
by SpaztiC829 March 25, 2009
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When, in a relationship, farting in front of each other is not acceptable. Breaking the sound barrier is the point at which the first fart takes place in front of the significant other.
I always have a tummy ache when I leave my boyfriends place.

Why?
Because we haven’t broken the sound barrier yet and I have wicked gas.
by Nimble July 22, 2018
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