Complex sentence: Both men and women experience quick cycles of muscle contraction of lower pelvic muscles and women often experience uterine and vaginal contractions; this experience can be described as intensely pleasurable, but roughly 15% of women never experience it and half report having "faked" it.
Split into simpler sentences: Both men and women experience quick cycles of muscle contraction of lower pelvic muscles and women often experience uterine and vaginal contractions. Roughly 15% of women never experience this and half report having "faked" it.