This really happened!
My sister-in-law often calls me to repair things around her house when her husband isn't around. On this particular day she called saying that her toilet was running and wouldn't stop and that her husband had taken the kids out of town for the weekend to give her a break and had no one to look at it. Since I live fairly close, I said I would be there in a few minutes.
When I got there she answered the door and thanked me for coming, and quickly brought me into the washroom where the toilet was indeed running. On the way through the kitchen I noticed her friend sitting at the table and politely said hi while passing. She left me in the bathroom to work on the issue, but I quickly realised that I required a few tools to complete the repair, so I went back to the kitchen and asked if her husband had any tools, of which she replied that they were out in the back garage and to help myself. So out to the garage I went.
I was rooting through his toolbox, when I started to get a bit horny. Looking around, I realised that the garage was fairly private and that no one could see me unless they walked up to the door and looked in the window which probably wouldn't happen since both women where busy talking in the kitchen. With my heart pounding in my chest, I pulled down my pants and underwear to my knees and started full on masturbating as quickly as I could with my eyes closed and my head fully rolled back enjoying the moment.
(Little did I know that my sister-in-law had come out to the garage to see if I was able to find everything I needed, and saw me with my pants down and had called her friend to come and witness what I was doing.)
I was still enjoying the moment when I got the feeling that I was being watched. I opened my eyes and quickly turned to the door to see both women staring at me. I quickly pulled up my pants without finishing what I had started. Seeing me do this they both opened the door and rushed into the garage. My sister-in-law quickly asked me what I was doing, I began to splutter a few words to explain how they had found me when she said, no, I mean what are you doing stopping without finishing?' I stopped spluttering and stood there in complete shock. She continued, 'finish!' motioning to me to drop my pants once more. I didn't move, and just stood there. She once again demanded 'finish! Obviously you need to, so finish!'
Hearing this I slowly pulled down my pants then my underwear to the knee as both women stood quietly watching, and began stroking once again. My sister-in-law piped in, 'no, remove them!', 'Remove them?' was my response, 'yes remove them'. She answered. So I slowly kicked off my pants and underware completely and resumed my previous actions. My sister-in-laws friend did not say a word throughout this whole event. My sister-in-law started again, 'No! keep going!' To this I was confused and she could tell by the puzzled look on my face. 'All your clothes' she continued. I started to protest but she gave me the look as though she was not going to take no for an answer. So I slowly removed my shirt and socks and stood completely naked and fully erect in front of both women. The friend, still silent, couldn't take her eyes off my naked body.
'Good' my sister-in-law continued 'now finish'. I continued stroking with one hand slowly as I rubbed my ass and body with the other, alternating between closing my eyes and rolling my head, and opening my eyes to see if the women were both still watching. This went on for several minutes as I grew more and more aroused and about to burst. I began to buck my hips and breath heavy. All of us knew what this meant so one last time I opened my eyes to see both of them staring at my throbbing cock just as I started ejaculating one of the most intense orgasms that I have ever had. I continued stroking slower now just to drain the last few drops and catch my breath. I observed as both women still speechless stood and starred.
After a few seconds, my sister-in-law picked up my clothes, and said 'Clean up this mess, get the tools you need, and come back inside to finish fixing the toilet'. I was shocked and asked how I was suppose to get from the garage to the house without any clothes. To which she replied 'that's your problem, and don't keep us waiting'. Then they both walked out giggling as I stood there naked, exhausted dripping cum and without clothes.
I quickly wiped up the floor, grabbed the required tools and shyly strolled into the house. I walked right by the women, partially erect again and right into the bathroom to complete my repair as instructed. The women pretended not to notice my nakedness, and held my clothes hostage until I completed the repair and returned the tools to their proper place.
Nothing more ever happened and we never talked about what happened that day, but I often masturbate to the memory of it.