Vaginismus is the inability to have penetration into the vagina with a penis, finger or tampon.
With Vaginismus, there is usually significant Connective Tissue Dysfunction that needs to be addressed first before internal work is completed. There are some good self-help websites including www.vaginismus.com On this website, a dilator and full instruction booklets are available. It is suggested that you follow up the self-help treatment for connective tissue dysfunction before embarking on the stretching exercises with the dilators. Think about the connective tissue like saran wrap. If the saran wrap is pulled too tight (the connective tissue externally between the rib cage and the knees, including the connective tissue in the vulvar area), than it stands to reason that penetration is very difficult.
Vaginismus may or may not have a significant fear component attached to it. There are wonderful sex therapists who can help in this area. Their website is www.bestco.info (Board of Examiners in Sex Therapy Counselling in Ontario).