Hitting a Wall
Depending on the intensity, penetration issues will range from minor burning sensations with tightness to total closure of the vaginal opening with impossible penetration. Many couples describe the feeling of "hitting a wall" when attempting intercourse.
This is often referred to as vaginismus, a pelvic pain disorder. Symptoms range from burning with tightness during sex to impossible penetration, even spasms in other body muscle groups.
Examples of the Effects of Vaginismus
Vaginismus is an involuntary contraction of the muscles surrounding the entrance to the vagina, making penetration painful and even impossible.
This involuntary vaginal reflex is a limbic system reaction, triggered by attempts at intercourse with the entry or approach of a penis to the vagina and, or by the insertion of other objects such as a tampon, a doctor's finger, or even your fingers. The spasms constrict the vaginal opening, making it virtually impossible to have intercourse.
A Limbic System Reaction
Naturally, sexual messages will vary among women, but many women will experience a conditioned reflex response in the vaginal muscle group during penetration. Even if there's a desire for physical intimacy or a will for tampon insertion, the limbic system tells the body "I'm going to protect you from harm" triggering pelvic floor muscles to go into spasm. It's an associated reaction.