What a good introduction to the girlfriend's parents. Although the stepmother is not her own mother. Still, she also decided to do her part in raising her stepson. The method she chose, it is true, is not the most popular - I have sex education. But I think it's a pretty brave decision. Considering that she is not his own mother, it cannot be considered incest; on the other hand, for this lady's husband, it cannot be called treason. Since it is his own son. Everybody wins!
Sunbathing naked on the terrace, sucking cock is cool for her. Especially since there's always a chance she'll get noticed by other vacationers. There's a chance to get famous and let other studs ride her pussy.