When I was sixteen, my bed-ridden mother passed away, and it was just my step-father and me. One day I had just got out of the shower, blinking water out of my eyes, when a large bag suddenly went over my head, and fell all the way to the floor, enclosing me in it. I struggled but he was too strong, and quickly had me tied inside it at the neck and waist, and was working the bottom back up and tucking it under the rope at my waist, leaving me exposed from the waist down, and utterly helpless, getting a little air through the zip that ran up the front of my face. Then he began to play with me, and to my humiliation, I became rock hard in a matter of seconds. He stood behind me, put something slippery on my asshole, and began to slowly penetrate me, very gently, but remorselessly, until he was all the way inside. All the while he was wanking me with incredible skill, and we stayed like that for hours on end, without any chance of coming, for me. I was crazy with need, but unable to do anything. It was incredible, and utterly addictive, and for the next twenty years, my evenings, nights and weekends consisted of varieties of these activities, until he passed too. Now I hope to meet someone, and I still have the bag, believe it or not!