Reason being, she could tighten her vaginal muscles.

Larger dilators are used over time to train the vaginal muscles.

Vaginismus: Involuntary spasm of the vaginal muscles during sexual intercourse.

"I'm coming," she moaned, and flexed her vaginal muscles several times.

If his wife has weak vaginal muscles.

In some cases, a woman may need to twist the cup or flex her vaginal muscles to ensure the cup is fully open.

The opposite is true, he said; painful intercourse can result if the vaginal muscles are too snug.

Rosamund clutched at him and her wonderful vaginal muscles set to work again.