This book is a friendly guide, not a medical text or a scientific paper. Where it describes research, it tries to say what the studies found in plain words and to be honest about how much is known. The notes below name the main sources, by day, so that you or a professional can check the work. Survey figures describe the people who were asked and the way the question was worded, and they change from study to study. Treat them as snapshots, never as a standard you have to meet.
A note on health. Nothing here replaces care from a doctor, nurse, or pelvic floor physical therapist. If you have pain, bleeding, leaking, numbness, a medical condition, or are pregnant or recovering from surgery or childbirth, talk with a clinician before trying the pelvic floor routines, the toys, or anything else that raises a worry. The pelvic floor guidance in Day 15 is general and is meant to be reviewed by a qualified clinician before each new edition.
Day 2: the orgasm gap and Freud
Frederick, D. A., St. John, H. K., Garcia, J. R., and Lloyd, E. A. (2018). Differences in orgasm frequency among gay, lesbian, bisexual, and heterosexual men and women in a U.S. national sample. Archives of Sexual Behavior, 47, 273 to 288. In a sample of about 52,600 American adults, the share who said they usually or always orgasm when sexually intimate was about 95 percent of heterosexual men, 89 percent of gay men, 88 percent of bisexual men, 86 percent of lesbian women, 66 percent of bisexual women, and 65 percent of heterosexual women. The figures are self-reports of recent sexual activity, and other surveys using other measures and populations give other estimates.
Freud, S. (1905). Three Essays on the Theory of Sexuality. Freud described clitoral sexuality as a juvenile stage that a mature woman was expected to leave behind for vaginal sexuality. Koedt, A. (1970). The Myth of the Vaginal Orgasm, a widely circulated essay.
Day 4: anatomy
O’Connell, H. E., Sanjeevan, K. V., and Hutson, J. M. (2005). Anatomy of the clitoris. Journal of Urology, 174, 1189 to 1195. See also O’Connell, H. E., Hutson, J. M., Anderson, C. R., and Plenter, R. J. (1998). Anatomical relationship between urethra and clitoris. Journal of Urology, 159, 1892 to 1897.
The pelvic floor cue. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) describes stopping the flow of urine as a way to find the muscles at first, and advises against doing Kegel exercises while urinating on a regular basis, because it can keep the bladder from emptying fully. See NIDDK, Kegel Exercises, niddk.nih.gov. Cleveland Clinic likewise says Kegels are not for everyone and that too many can leave the muscles too tense. See Cleveland Clinic, Kegel Exercises, my.clevelandclinic.org.
Day 5: how desire works
Basson, R. (2000). The female sexual response: a different model. Journal of Sex and Marital Therapy, 26, 51 to 65 (responsive desire). Bancroft, J., and Janssen, E. (2000). The dual control model of male sexual response. Neuroscience and Biobehavioral Reviews, 24, 571 to 579, and its later extension to women. Nagoski, E. (2015). Come As You Are, for a popular account.
Days 7 and 8: attention, spectatoring, and closeness
Masters, W. H., and Johnson, V. E. (1970). Human Sexual Inadequacy, on sensate focus and spectatoring. Brotto, L. A. (2018). Better Sex Through Mindfulness, and Brotto, L. A. and colleagues’ trials of mindfulness-based treatment for women with low desire and arousal difficulties. Diamond, L. M. (2008). Sexual Fluidity.
Day 9: the stages of response
Masters, W. H., and Johnson, V. E. (1966). Human Sexual Response. Boston: Little, Brown. The description of arousal, plateau, orgasm, and resolution, and the roughly 0.8-second rhythm of orgasmic contractions, come from this work. Later models added desire.
Day 10: the button, the kitty, and the G rumor mill
Herbenick, D., Fu, T.-C., Arter, J., Sanders, S. A., and Dodge, B. (2018). Women’s experiences with genital touching, sexual pleasure, and orgasm: results from a U.S. probability sample of women ages 18 to 94. Journal of Sex and Marital Therapy, 44(2), 201 to 212 (published online 2017; doi 10.1080/0092623X.2017.1346530). About 18 percent said intercourse alone was enough for orgasm, and nearly three in four said clitoral stimulation was necessary or made intercourse orgasms better.
Gräfenberg, E. (1950). The role of urethra in female orgasm. International Journal of Sexology, 3, 145 to 148. Ladas, A. K., Whipple, B., and Perry, J. D. (1982). The G Spot and Other Discoveries About Human Sexuality, which popularized the name.
Day 11: first time or next time
Heiman, J., and LoPiccolo, J. (1976, revised 1988). Becoming Orgasmic: A Sexual and Personal Growth Program for Women. The text says only that directed programs of this kind report encouraging results.
Day 13: when pleasure is hard
Komisaruk, B. R., Whipple, B., Crawford, A., and others (2004). Brain activation during vaginocervical self-stimulation and orgasm in women with complete spinal cord injury. Brain Research, 1024, 77 to 88. The medicine, hormone, and menopause passages are general; readers with these concerns should speak with a clinician and never stop a prescribed medicine without advice.
Day 14: toys and boosts
Herbenick, D., Reece, M., Sanders, S., Dodge, B., Ghassemi, A., and Fortenberry, J. D. (2009). Prevalence and characteristics of vibrator use by women in the United States. Journal of Sexual Medicine, 6, 1857 to 1866. The text’s statement that research finds little evidence of addiction to devices as such is a general summary and should be confirmed by a clinician at each edition. Prescription options for low desire are for particular situations and require a prescriber.
Day 15: the pelvic floor
The statement that stronger pelvic floor muscles are associated with better arousal and orgasm in some studies is described in the text as developing evidence. Examples: Kegel, A. H. (1952). Sexual functions of the pubococcygeus muscle. Western Journal of Surgery, Obstetrics and Gynecology, 60, 521 to 524, and later studies of pelvic floor muscle training and sexual function. Readers with pain, leaking, prolapse, pregnancy, or a recent birth or surgery should have a pelvic floor physical therapist assess them first.
Days 16 and 17: kinds of orgasm and touch-free pleasure
Komisaruk, B. R., Wise, N., Frangos, E., and others (2011). Women’s clitoris, vagina, and cervix mapped on the sensory cortex. Journal of Sexual Medicine, 8, 2822 to 2830, and Komisaruk’s work on nipple stimulation and the brain. Kinsey, A. C., Pomeroy, W. B., Martin, C. E., and Gebhard, P. H. (1953). Sexual Behavior in the Human Female (orgasm in sleep). The source and makeup of female ejaculate remain debated; the text describes this as unsettled.
Whipple, B., Ogden, G., and Komisaruk, B. R. (1992). Physiological correlates of imagery-induced orgasm in women. Archives of Sexual Behavior, 21, 121 to 133 (a small sample, a few women succeeded).
Day 18: movement and the coregasm
Herbenick, D., and Fortenberry, J. D. (2011). Exercise-induced orgasm and pleasure among women. Sexual and Relationship Therapy, 26(4). The sample was 370 women who reported exercise-induced orgasm or exercise-induced sexual pleasure, ages 18 to 63. Among those reporting orgasm in the previous 90 days, 51 percent linked it to abdominal exercises, 27 percent to weight lifting, 20 percent to yoga, and 16 percent to bicycling. It is a self-selected survey and does not show how common the experience is.
Days 20 to 22: sound, imagery, and erotic media
The ASMR figure (about one in twenty listeners using it for sexual stimulation) comes from small online surveys and should be read as a rough indication only. See Barratt, E. L., and Davis, N. J. (2015). Autonomous sensory meridian response (ASMR): a flow-like mental state. PeerJ, 3, e851, and Poerio, G. L., and colleagues (2018). More than a feeling: autonomous sensory meridian response (ASMR) is characterized by reliable changes in affect and physiology. PLoS ONE, 13, e0196645.
Surveys of fantasy and erotic media: Lehmiller, J. J. (2018). Tell Me What You Want. Joyal, C. C., Cossette, A., and Lapierre, V. (2015). What exactly is an unusual sexual fantasy? Journal of Sexual Medicine, 12, 328 to 340.
Day 27: the zipless encounter
Jong, E. (1973). Fear of Flying. New York: Holt, Rinehart and Winston. The novel coins the zipless encounter: a sexual meeting between strangers with no emotional commitment, ulterior motive, or power game. The scenes in this book that involve other people are invented, private, and consensual, and the public-transport practices are hands-free and unseen by design.
A note on the stories
The named women in the Happy Discoveries and Stories are composite or invented characters, not case histories, and are not medical evidence. Any resemblance to a particular person is coincidence. The Private Wing vignettes are fiction for adults. Every person in them is an adult who has said yes, and anyone involved can change the answer at any moment.
A note on clinical review
The author is not a clinician. The pelvic floor routines, the medical sections (Days 12 to 15), and the comments on medicines and pain should be reviewed by a licensed physician or pelvic floor physical therapist before publication, and all statistics and citations should be checked against the original papers (the survey figures above were checked against the published abstracts and summaries while this edition was prepared). Corrections are welcome and will be made in later printings.