Hi Terry--Good question; I can definitely answer this. A few Q's first, though:
-What is the AGE of your girlfriend (this has direct relevance)?
-During most lovemaking, does her vagina tend to: (a) Get VERY moist easily; (b) NOT get moist much at all; or (c) In between (moderate) ?
-Has she borne children yet--if so, how many?
-How many sexual partners did she have before you?
Please note that your well-thought out responses to these questions will
greatly assist me in narrowing down the possible diagnoses, so I can reply to you
with more accurate and helpful medical advice.
Thanks, --Dr. Steve, Your Online Family Doctor
Thanks Terry--put simply, there are 2 Main Determinants:
1. Hormonal (esp. Estrogen) Levels: the HIGHER the estrogen level in her system, the TIGHTER her vagina will become.
2. Voluntary & Involuntary Muscle Contractions: This is PARTLY under her control (i.e. can be affected by her mood; her emotions toward you at that PARTICULAR moment; the type of day she had, etc); and partly INVOLUNTARY (more of a brain reflex, that suddenly sends an 'electrical signal' to the vaginal muscles, if you will).
This is the simple version answer (for brevity sake); actual Neuro-Hormonal Physiology is extremely complex (my med school textbk was over 1,000 pages), and would probably take a few hours for me to fully elaborate.
I hope this was helpful--if so, please hit **ACCEPT** as you read this, so JustAnswer will give me credit for my time; THANKS !
Best regards, -Dr. Steve
Theoretically--YES, that is possible; but of course, masturbating (esp. w. sex toys, dildos) can also impact the size and 'tightness'.
Please hit **ACCEPT** , then I can respond further if you wish.
Thanks, -Dr. Steve
Different things can cause a size difference. As Dr. Steve Mentions above, sex, Masturbation and hormonal changes can cause a difference. Other things can be attributed to this as well. Her mood, If she is not in a sexual mood you may experience more tightness. Also little things like Depression, menstruation cycles (If she is not menopausal) Yeast infections, UTI can cause a difference in tightness.
Tightness can vary from day to day and can be caused by any of these things though mood is the most common. The more sexually stimulated she is the less tight she will be. Thus said the less sexually stimulate she is the tighter she will be.