hoverfly

As BindiCat said, there is no guarantee that a woman that has given birth several times will have a large vagina. We've had two children but due to the PC muscle exercises (also known as Kegel exercises) she, at the age of 50 now, has a fanny that'll happily crack nuts anyday.

BTW, those exercises are not only recommended for women whose partner has a small penis but also in general as it can help prevent incontinence in later life, plus their sex life will benefit greatly from these efforts.