The brother had an epiphany when the two sisters gave him their pussies. The look on his face was epic. The Asian girl gave him such a great present for the new year, that the brother obviously did not expect. The Asian girl decided not to pull the cat by the tail and got down to business right away, as long as there was an opportunity to use it. The threesome was a success, cum just poured out of his sister's pussy.
I don't know. I don't find that ass arousing.