mom-off

Its like a complete turn off.

But, your mom causes it by coming by your room late at night to say good night or in other cases "GO TO BED".

Before she came you were probably masturbating and looking at porn.

You will lose your boner and feel tired and shitfaced.

Chris is jacking off at porn with his friend Jack.

Chris's mom comes to say goodnight at the sleepover.

Jack whispers, "What a mom-off."

Chris replies, "Yeah."