Younger Daughter: Elementary school student 4th grader, 8 years old.
Elder Daughter: High school student. 15 years old

After my wife passed away a few years ago, I have been living alone with my two daughters, with whom I have an unusual father-daughter relationship.

While my eldest daughter already has plenty of practice thanks to my advanced sex education classes, my youngest daughter lacks experience on the subject, so I thought it would be a good time to start classes.
My girl is still very young and her immature little pussy couldn't handle more than the tip of my penis, so for the time being, we decided to stick to anal sex. After a generous amount of lube, her tiny asshole was ready to accept my dick so I penetrated her anus steadily while holding her by the waist. I immediately began pounding her little ass, moving back and forth, causing her to moan with each slam.

Suddenly my oldest daughter walked into the room... time stopped for a moment...

-"Hey... Mayu... you are awfully early today... ha ha ha..."
-"Mayu oneechan... Welcome home!"
-"... DAAAAAAAAAAAAAAAAAD!!!..."