You were starting to enjoy penetrating your aunt's butthole, as you were both now naked, and still in the cave where you were following the woman with dark hair. Of course, you thought it was wrong because your aunt was part of your family, but seeing how she was enjoying it too, you couldn't see any exact problem.
That was, until you noticed that your aunt was getting much bigger than usual. You knew that your aunt was big when you were a child, but you didn't think she would gain so much in size. Just then, you noticed a muscular arm come out from behind your aunt where she was holding still. Then, you took a look at your aunt's backside, and figured that something was wrong. Just then, you came as you felt two testicles form, and touch your testicles, before you could pull out.