When your doing a girl doggy style on the top of a staircase. She needs to be holding on to the top stair and you yell "mush" thrust as hard as you can and ride her down the stairs.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.