We asked a very close brother and sister to take on an exciting mission that would test their bond! To make it even more exciting, we had the brother take Viagra and have the two stay under the same roof for an extreme experience! As time goes by, the brother's crotch swells up and his face takes on a man's face, and the sister is confused, saying, "We're brother and sister..." but her pussy can't help but throb at the brother's fully erect dick! The two are so excited that they don't think about the consequences and head straight into breeding mode!