Scientists have determined that the average time of intercourse lasts 4 min. The average number of strokes is 9 per minute, making the average intercourse 36 strokes. Since the average length of a penis is 6 inches the average girl receives 216 inches or 18 feet per intercourse. The average woman does it about three times a week, 52 weeks annually. 156 x 18 feet makes 2808 feet or just over a half of a mile.