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.

a phrase chiefly used in northern England.

it is a contracted form of "it'll be reet", where "reet" means "alright" or "OK".

living your life according to "be reet" is the only way to find happiness in life.