Two things. First an update.
"I got your second response and took the advice. I called my sister and got a very hearty "Please!" when I suggested a talk with her son. "Jesus Christ, maybe he'll calm down a bit if he knows he's got permission to jerk off." So, the talk went well. He understood my misgivings about dropping trou and showing him, as my wife suggested. Judging by the amount of paper towels in the waste basket, he thoroughtly enjoyed the clips you suggested. The questions after were straight-forward and easy to answer. I think he's actually relieved to find out he's just a normal horny teen."
Well, so there ya go. It's easier than we all fear when we face The Talk. The next email was a bit onerous at first.
"Why do gay dudes love taking it up the ass so much?"
Well, pardner, it ain't just gay men who enjoy that. You've heard about the women's G-Spot? Well, for men, there's this thing called the Prostate. Manipulating and stimulating it increases the hardness of a boner, and it feels really good.
Look up "pegging" and you'll discover that straight men "love taking it up the ass," too.
External pressure, or pushing a finger in...
And, though not too many will openly admit to it, but leave them alone in a room with their wife's or girlfriend's vibrator....
There's so much more to sexual pleasure than your cock.