Many years ago I was a young Lieutenant in a ship in the Mekong river of VietNam. I had a beautiful, sexy wife at home port in the States. It was about the time when the first cassette recorders became available and I thought it would be more intimate to hear each others voice on tape than to just see handwriting on paper, so I bought two and sent her one.
Our early exchanges were pretty routine family stuff as we got comfortable with the recording process. But very quickly I had to tell her how hot her voice sounded and how I missed our sex life. She responded by telling me how horny she was all the time and how much she missed my hard cock. I told her that the thought of her wanting my cock made it stand up and that I had it in my hand as I listened to her. (Since I was the ship's Captain I had the needed privacy.)
On her next tape she said how she wished she could see me masturbate, how hot it would be to watch me stroke and squeeze my cock and shoot my cum.
Then I heard it, that unmistakable buzz of a vibrator. The picture in my mind of her with her legs spread, that beautiful wet pussy, and that vibrator head on her swollen clit made me crazy with lust and longing and I jerked my cock like a mad man. Then came the most exciting sounds in the world; her moaning, heavy breathing and grunting as the first of multiple orgasms swept over her and I came like never, ever before.
And that's the way we ended every tape thereafter.