You dad has been gone for a very long time and mommy has been thinking about how she would like to complete the family. You are old enough to impregnate her, so she wants to put your sperm to the test. Mommy comes in to tuck you in as usual but tonight she lingers a little bit longer when she is kissing you good night. Then she explains she will do all the work and all you have to do is lay there and let her knock herself up using your cock. She really wants to get pregnant. Mommy gets you hard and then mounts you, lovingly teaching you how to fertilize her.