The following is an excerpt from the National Organization of Circumcision Information & Resource Centers, Colorado site.
During intercourse with an intact penis, the vaginal walls grip the outer penile skin, and the penis slides back and forth inside its own skin. This causes very little friction against the vaginal walls. This motion is smooth and effortless and creates a very pleasurable sensation for both the man and the woman. Women who have had intercourse with an intact man describe a sensation of being perfectly and seamlessly connected to their partner.
During intercourse with a circumcised penis, the skin on the penile shaft rubs back and forth against the vaginal walls, and this is often the cause of sexual discomfort for women. Many women whose partners are circumcised need artificial lubrication to reduce friction and discomfort, but for women who have intact partners, artificial lubrication is unnecessary. Because few women in America have experienced intercourse with a natural penis, most don't understand that circumcision is a major cause of uncomfortable vaginal friction.
Studies have shown that women who have intact partners have greater levels of sexual satisfaction than women who have circumcised partners. They also have greater success reaching orgasm through intercourse. A recent survey showed that of American women who had experienced both kinds of intercourse, 89% preferred intercourse with an intact penis. These women also reported improved success at achieving orgasm through intercourse with an intact penis. Also see what Dr. Dean Edell had to say on this subject.
Marilyn Milos, RN, CPM, details further how circumcision changes intercourse for both men and women:
For more information see:
* Article: How Circumcision Hurts Women by Jocel Them
* Article: Functions of the Foreskin by Dr. Fleiss, MD and Dr. Hodges, PhD
* Article: Improve Marital Sex: Keep the Foreskins by Dr. Dean Edell, MD
* Crystallized Pathology: The Clitoris, the Penis, and Women's Sexual Health by Danelle Frisbie, PhD, MA (drop me a note if you'd like a pdf excerpt version)
* Website: Sex As Nature Intended [graphic site]