Only out drip tube and not while running or under pressure. Only when engine is shut off and heat soaks. Pressure goes up and it dribbles till it cools down a bit.
No actually the pressure goes down, the coolant boils at a lower temperature and that's when it dribbles. 1# of cooling system pressure will raise the boiling point 3°. You loose pressure (15#) and you are back to water boiling at 212° (depending on coolant strength and altitude)
