This is a true story. I needed to get a sigmoidal scope done at my doctor's office. Before having this done I was instructed to clean out with an enema, the Fleet kind. My 65 year old mother-in-law is over every day watching my two year old son, since both my wife & I work.
On the procedure day, my wife had already left for work, and since my appointment was for 10:00am, my mother-in-law was already over. I told her that my wife left without helping out with my prep enema, and would she mind doing it for me. She hesitated at first, then said, what the hell, if you are OK with it, I'm OK with it. So, I went up to the master bedroom, put down a towel, got on the bed on my hands and knees with my ass and balls open for inspection. She came upstairs, put the nozzle in, and squeezed the bottle. She had a perfect view of my asshole and balls, and I was loving it. She was even twisting the nozzle in my ass. I was getting harder knowing she was looking. When the bottle was empty, I slowly got up, turned around to show her my semi-hardon, which she 'studied', then I went into the bathroom to empty out, and 'rub' one out too.
To my suprise she walked in to make sure everthing was OK. She looked at me with my dick in hand, and said she was sorry for interupting. I said wait, no problem, come back in. Then she watched me cum in in my hand. I think she was more shocked than anything, but not mad. Later on in the summer, at the beach, I asked my wife to put lotion on my back, and my mother-in-law said she would do it. I said that's OK, and in a quite voice she said, no problem, I've seen 'everything' already, so you can't be too embarrassed.