When two people have the same thought at the same time, as if it were telepathy. The reason for calling it a Mountain Dew moment is because the type of telepathy originated when two found girls both made the same stupid mistake when referring to caffeinated beverage. Instead of thinking about Coffee, Mountain Dew popped into their heads. Therefore creating the Mountain Dew moment.

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.