I overthought this and wondered if a 48" thing can really go all the way in, but I was surprised to know that “The average erect penis is longer than the average vagina. ” and that it’s not really possible to ‘break through’ the cervix and go further.
Even ignoring girth, it’d probably be very painful for her (without training, I suppose) if someone just rams their 40" into her.
And I forgot that large loads can go by the back entrance. XD
It’s probably have enough to accommodate 48" (with enough training), or even more.