This takes a while, until you feel a change of rythm of the dick inside you. He is going to cum! The moment you realize, you are filled with warm fluids. As it fills you, you leave out a high pitched scream, first shrill, reflecting your surprise of sudden hot fluids filling your insides, when getting lower as sperm disperses through your inner organs.
This was exciting and fun! You sit up and look at your exhausted boyfriend. Happy about your experience, you smile at him.