I have boys. My husband and I have always had open communication about anything and everything with them. If they were old enough to ask, they were old enough to know. I did not allow street slang for body parts. They had to use the correct word or I wouldn't discuss sex with them. If they didn't know the proper word, we looked it up together. Back in those days I kept many medical books.
Morals and values are not only taught, they are learned from watching. In a perfect world there would only be sex with love but life isn't perfect. You do what you can to help and protect your kids always hoping for the best. I would have done the same things if I had a daughter.
Humor DOES help.
The stories I could tell.
Having one of each....it's always been easier to talk to my son regarding sex. I think you are right, that humor was/is a help. Even at 28, he still comes to talk to me/us regarding his personal life. He's in a bit of a dilemma now, trying to make a relationship work when she lives halfway across the country...and has asked our opinion on a variety of issues. Pretty neat, to have him even want to know our opinion.