[Grant69]

Unfortunately my wife doesn't have any sisters but I did once see her mother naked.

It was when my MIL was staying with us for the weekend and my wife was out shopping. I was in our bedroom doing some repairs or something and MIL came in asking me if she could have a shower, which was in our en suite. Of course I said yes and didn't think much of it as I returned to my work. Several minutes later I heard footsteps behind me and as I turned round, I saw my MIL walking towards the door wrapped in a towel. I must admit it perk my interest but she soon disappeared into the en suite and started the shower running. A few minutes later I heard the door open and a voice asked if I could get her shampoo from her room that she'd forgotten. I did as I was asked and on returning to the room I saw the en suite door was still open a few inches. I went up to it and shouted that I'd got the shampoo as asked. No response. I repeated what I had said but still nothing. So I opened the door a bit more and held my arm out with the bottle in front of me. At this stage I began to think there was something wrong so I poked my head around the door and saw to my delight my MIL in the shower, facing towards me with water running down her naked body, giving me a great view of her nudity. Her tits were certainly saggier than the wifes [which I suppose you would expect] but smaller too with erect nipples. Her pubic area was covered with hair [albeit mostly above her pussy lips] and was quite grey, whereas my wife has always kept her pubic hair which was still jet black.

She didn't seem to mind that I had seen her in all her glory and opened the shower door so I got an even better look. To my shame I felt an erection forming in my pants as she reached out and took the shampoo with a smile on her face. I immediately retreated outside and shut the door behind me. I sat down on the bed and couldn't help feeling so very horny picturing what I had just seen.

As an aside, I took off all my clothes as I heard the water in the shower stop and put a towel over my lap. When she emerged from the en suite with a towel around her, I told her I was going to have a shower as well. As she looked over, I stood up and let the towel over my lap fall to one side - I just wanted to let her see my erect penis I suppose. When I got in the shower the first think I did was masturbate replaying the sight of her fully frontal naked in my mind.