She Never Knew I'd Seen Them Twice

This confession is about two seperate incidents several years apart but they are connected.
It's how seeing my sisters tits completely by luck of being in the right place right time is much more memorable than any deliberate attempt to maybe catch her at the right moment undressing.
The first time was when she was aged 19. I am four years older. We were both still living at home with our parents at the time. They had been invited to visit relatives in Canada for a month, and trusted me and my sister to look after the house ourselves. It was midsummer and we were enduring a heatwave. One evening my sister came into the living room and spread her stuff on the low coffee table that is infront of the sofa. Think it was mostly nail varnish and remover. She was wearing just her pyjama top, which I was about to find out was very loose fitting. She had just two buttons done up. The last one to stop it opening and showing her knickers, and one more button about level where her bra would be. I was sitting on an armchair where I could watch the TV and also see her. Every time she was leaning forward I was seeing some cleavage but no more than I had seen before. After some time she said, "I'm all done, I'll be back downstairs in a moment". She stood up, and bent over from the waist to pick up her stuff. As she did so her pyjama top fell away from her body giving me a clear view down her top. at her big 34DD tits hanging totally free like two giant water balloons. Swaying about, bumping together. It will be a 30 seconds I will always remember.
The 2nd time was six years later when she would've been 25. By now she was living alone in her own house. It was a Saturday afternoon on a hot summers day. I had been visiting a friend that morning and was now walking to the towns shopping area. My walk took me along the road that my sister lived in. As it was a really hot day I decided to knock on her front door to maybe grab a cold drink or a cup of tea. I rang the doorbell and waited. There was no answer. I guessed she must have gone out. Then for some unknown reason before I was about to walk away, I tried the door handle. It went down and the front door opened. My immediate thought was that she has gone out and forgotten to lock the door behind her. I better go in and check all is ok before leaving. I walked down the hallway into her living room where I noticed the door out to the patio was open. The I saw her, well I saw her feet and lower legs to be exact. She was sunbathing on her sun lounger. I moved to a position where I would be behind her head but then noticed she had her face covered . I thought I will just have a quick look at what her bikini looks like before I sneak out but as I moved closer to the window I realised at first she was topless and then realised she was sunbathing fully nude. Her big tits topped with dark areolas that are at least 4 inches across. They are like car headlights on full beam. Then down to her c**t. This was the first time I had ever seen it . She had a full bush of very thick black pubes. Her bush was rectangular in shape rather than inverted triangle. It was obvious she had never shaved it as the pubes were so thick. I quietlly left and shut the door, but deliberately didn't lock it.
She has never to this day known I was there. As I walked away I did think what if it had not been me that found her front door open. What if it was a group of men looking for easy burglary targets and done the same as me.
Hope you like my story.