This is a controversial procedure and one I would initially discuss with your gynecologist.
It is important to first determine if you are in need of reconstructive vaginoplasty , also called and anterior or posterior repair, which is considered to be a procedure for "tightening" and restoring the the vagina damaged commonly through birth trauma. It may be related to multiple births or large birth weight babies and is commonly seen following uncontrolled tears during the birthing process as opposed to surgical episiotomy. Women tend to have other related complaints such as bladder incontinence (leakage) and occasionally fecal retention (difficulty with complete evacuation) due to the conditions of cystocoele and recotcoele combined.
When it comes to vaginoplasty, I highly recommend you seek the attention of your gynecologist for an initial exam to determine if there was specific damage caused by the birthing process or an episiotomy. It is not unusual to have associated conditions such as pelvic laxity, uterine prolapse, and or stress urinary incontinence to name a few. Some urologists or urogynecologists may also perform these reconstructive procedures. If you live far away, it will be difficult for me to give you any specific referrals so please seek the recommendations of your personal physician/gynecologist.
Should you desire elective vaginoplasty which is essentially making your vagina smaller, or repair of your episiotomy such as a perineoplasty, this is something that is most commonly performed by approximating the levator muscles along the back wall and floor of the vagina when laying on your back (supine postion). In some ways, it is similar to the muscle repair performed during a tummy tuck.
This is not a procedure that should be undertaken without a serious review and discussion of the risks. The American College of Obstetrics and Gynecology considers this a medically unnecessary procedure.
The following video reviews some of the pertinent anatomy.
I hope this answers your question.