Nice girls don't even finish. Since they don't practice fellatio frequently, their mouths get tired and they stop. You have to literally sit on their chests and beat them on the cheeks and lips in order to finish your liquid launching.
Speaking of which, I just saw the DVD of "A Series of Unfortunate Events" in the library. Gawd DAYAM, does that girl have the best, penis-massaging lips you've ever seen?