Everything in this family is through the ass - the daddy spanks the daughter, the mother sucks the son. And in order for the husband to fuck his wife again, she had to seduce her daughter. It seems that they themselves are already confused who fucked who, but nevertheless, everyone is in a New Year's mood and there is enough pussy for everyone.
Well I do not know about the undeveloped ass, in my opinion a man very intensely and without preparation fucks a lady in the ass, and she gets a lot of pleasure out of it! So I think the ass is quite well developed.