TBF if I had some kind of radical surgery like that I would be looking at it too and trying to work out how my body now works.

Yeah, I think everyone would be curious. And initially post-surgery, you'd have to look in order to be sure everything is healing okay, just the way women who get episiotomies and tears during childbirth do in the weeks afterward to check their healing.

Jazz Jennings did a lot of looking at his reconstructed crotch after his surgery - which was understandable and seemed appropriate. Less appropriate was the way his other family members looked too - especially Jazz's always inappropriate mother. She took and sent so many photos of Jazz's fauxlva to Jazz's surgeon Marci Bowers that Bowers remarked on the TV show that Jazz's mum could get a job shooting pornos. (It was one of the many inappropriate, jaw-dropping things Bowers said and did on the show.)

But in a short reddit post, this person twice mentioned the appearance of his fauxlva when aroused - and he also expressed fear that his fauxlva looked "old." Seems like a very male way of behaving and thinking. Boys and men are used to seeing their dicks when they're sexually aroused coz their erect dicks are right there in front of their eyes - and usually in one of their hands too, LOL. And they're used to describing their erect dicks too - hard, throbbing, giant, thrusting, handsome, manly, studly, sturdy, like a giant oak, a cannon...

But because of our different anatomy, girls and women are not used to seeing our genitals when we're aroused - ours are tucked away out of our own sight all the time, aroused or not. The only females able to see their own genitals without the use of a mirror or camera would have to be contortionists.

Unless girls and women do porn or are prostitutes, or are TIFs taking T who are focused on and boasting about clit growth, or come from households where for some there's an emphasis on the appearance of the labia, or have gone through FGM or another genital trauma, it would seem that most girls & women don't spend a lot - or any - time thinking about or describing what our aroused genitals look like. Or at least that's my impression. Although I have heard some young TIFs on social media describe the changes in their clits in some detail, with lots of embarrassing macho posturing and lingo, and it struck me as decidedly odd. Also, I know that labiaplasty amongst women is a growing trend nowadays. But still, looking at your labia when aroused and fretting over its appearance does seem like a fairly niche concern, no?

What I want to know is the mechanics of this disappearing flesn during arousal. Is it ball sac skin that tightens? Does the fauxgina essentially work as erectile tissue?

It could be scrotal skin that become engorged. My understanding is that after the contents of the scrotum are removed, the sac skin is used to construct fauxlvas in these guys. WebMD says that

The skin of the scrotum thickens and the testicles increase in size usually by approximately 50% at the height of arousal.

Even with the testicles themselves gone and the scrotal sac rearranged, I'd imagine that the skin of the scrotum would retain its capacity to thicken and grow upon arousal.

Also, my understanding is that the surgeons who do these awful operations like to use the glans of the penis or other penile tissue to make a fauxclit in the fauxlva. When Jazz Jennings had problems urinating after his first surgery, the doctor said it probably was because the rerouted urethral opening was surrounded by and being squeezed by erectile tissue.

As for the interior pelvic pocket that is the fauxgina, whatever it's made of I don't think this man-made creation "essentially works" in any way. It seems to be a sleeve of flaccid skin meant to be used solely as a passive fuck hole that has to be routinely dilated to stay open and constantly washed out with strong, harsh chemicals coz of all the harmful bacteria that tend to grow there.