Couldn't have planned it that well
I have a webcam on my desktop computer that i can record with when my screen is off and there is no way of anyone knowing it is recording, I have it set up in my home office and as we don't have a spare room anymore since our kids wanted their own rooms we set up a murphy bed in the office, Its pretty cool and looks like a bookshelf when folded up.
My mother in law is very prim and proper and is a quiet person and stays with us often and i have been able to get a couple quick clips of her dressing or undressing before or after the shower when my wife's dad isn't there, This morning was a bit different since we got home kind of late after attending my wife's cousins birthday party and she didn't shower before bed. This morning she came up and had coffee and after coffee she said "Geez, I need to go shower to try and wake up a bit".
My wife was still sleeping and I had planned on turning on the cam as i usually do when the opportunity presents itself and after a few minutes i went downstairs and through the frosted glass doors i could see she was still in the room, I was going to sneak back upstairs but I could tell she was sitting with her back against the headboard and couldn't tell for sure but i thought she was naked, I could only see a vague outline of her but i heard her clear her throat then take a deep breath and let out a sigh.
I was already hard but didn't want her to see that so i hid it as best i could and decided to go for it, I flung the door open and looked right at her. She was sitting against the head board with her knees spread and the bottoms of her feet together, She had one hand spreading her kind of hairy p**** and the other rubbing her c*** which made her arms squeeze her medium sized, saggy b**** together and her big brown nipples were rock hard. She is 54 and had my wife at 22, She is decent in the looks department and her body is not too bad either.
My eyes got big and she froze covering her p**** with both hands as i whispered "S*** i thought you were in the shower...I'm so sorry" then as i turned to leave she jumped up and grabbed her house coat. I closed the door and quickly adjusted my h****** so it was fully visible as i headed for the stairs and just as i reached the stairs she opened the door and said "Wait", I stepped up two steps then turned to face her as she stood at the bottom of the stairs, She looked right at my b**** and whispered disapprovingly "Oh geez" and turned her head then turned back looking at me and said "I um, Just um, I don't um" and i interrupted her whispering "I am so sorry, I was just going to grab my keys off the desk and i thought you would already be in the shower".
She was super embarrassed as you can imagine and had her hands over her nose and mouth with her eyes closed and shook her head then took a deep breath letting it out then looked at me and i said "look, I will never say anything, No one needs to know, It was totally an accident and i feel horrible", She just kept closing her eyes and shaking her head but i caught her looking at my bulge at least a half dozen times as she tried to speak but couldn't. Finally i said "trust me...You have nothing to be embarrassed about, i am the one who walked in without knocking".
She looked right at my crotch and stuck her hands out and whispered in an angry tone "Why are you hard, Why...Stop that", I looked down and adjusted it and said "F***...Sorry...I just...And you look great to be honest", She interrupted me and whispered "Whoa...Inappropriate" After she scolded me for not knocking she said "Ok...No one EVER knows about this, No one EVER hears about this" and i agreed.
I went back upstairs and after a shower she came up, My wife was awake by that time and we never spoke about it again but i have obviously thought about it...MANY times.