I think she's exploding because she got an enema...(don't ask me how I know this but) what they do is give the girl an enema and then plug her up....the pressure builds up inside of her and when she gets unplugged....KA-BOOM!!!! all of this recorded for sickos the world over to enjoy....
and while I'm on that thought....Japanese porn is very interesting...scat seems to be pretty popular...there's tons of b&d....and you sometimes wonder if these girls are doing it of their own volition...anyway, the showing of genetalia is pretty taboo over there so you never see actually penetration or anything...just all the juicy stuff