The vagina does strech and is suppose to (for child birth is one reason). Yes the vagina is elastic and will contract it may take time. Kegel exercises help with the muscles and helping to make it tighter.
so ur wall cant expand no otha way than having sex and kegel is goin to help it close??
From what I have read the wall doesn't expand like that. But if you are fingered or you use a toy it can cause it to strech to accomdate the large size. Using things like Kegel excersies can help you.