My mother and I have been having sex for nearly 16 years this November. It started when I was 28 and she was 49 and at the time my step father was dying of cancer.
It started out casually enough but after a few days of having some amazing sex we decided we did not want what we had between us to end. My mother has always had me cum inside her and she almost always climaxes when I do.
(Warning: Extreme Sexual Taboo Content - 18+ ONLY!)