I was about 16 at the time (by then a daily masturbator myself) and I was sleeping over at my friend's house one weekend. We had both been asleep in her bed but something woke me and I couldn't get back to sleep. I decided to go to the kitchen to get a glass of milk.
I moved out of bed slowly as to not wake her. I knew I had to sneak out of her room and into the hallway, and go past the opening to the living room to get to the kitchen. It was pitch black in her room and I could barely see anything, but once I opened her door, the room was flooded with light because someone had the TV on in the living room. I tiptoed up to the edge of the living room door and peeked around the corner. It was my friend's dad, sitting on the couch and watching TV. I remember it was 'Rhonda's UP All Night' show, because I heard Rhonda's squeaky voice say 'UP all night!' like she did. Then my attention was brought back to the dad. His arm was moving rhythmically and immediately my heart started POUNDING, I knew he was masturbating!
If I got caught, I would have been humiliated. I knew her mom and little brother were also asleep, hopefully, somewhere else in the house. But my throbbing clit and horny little mind had me positively rooted to the spot. The dad had on pajama bottoms and a white tshirt; his cock was pulled out of the opening in his pajama bottoms. His left hand lay flat on his thigh, and he used his right hand to stroke, stroke, stroke it.
I watched in utter fascination. He stroked it up and down, up and down, stopping occasionally to swirl his thumb around the head. Moving back to the shaft, his speed quickened, and the next thing I knew, his left hand grabbed a towel and he spurted into it, making an awesome face and sort of arching his back when he came. Unfortunately for me, the towel had covered what I most wanted to see, gobs of cum squirting out of his big daddy boner.
He replaced his cock into his pajamas, and put the towel on the floor, then laid down on the couch and continued watching 'Rhonda's UP All Night'.
I took a few steps back toward my friend's room and noticed that my panties were absolutely soaked. I knew there was no way I could go back to sleep without fingering myself off. I had no choice but to go back to her room, past the bathroom and every other room in the house. I went back to bed and lay next to her like before. I could tell she was still sleeping by her deep heavy breathing.
I pulled my nightgown up and slipped my hand into my panties. My clit was hard as a cock and so wet and slippery to the touch. I used my middle right finger to flick it back and forth. I must have been shaking the bed pretty hard, because my friend awoke and stirred, but then she rolled over to her side and seemed to go back to sleep. I continued on, doubly excited by the thought of masturbating right next to my innocent sleeping friend, half wishing she would awake and join me in a little impromptu 'lezziefest' between two previously straight girls, and half wanting to be alone and just think of her dad furiously jerking on his horny dick. It wasn't long before I was cumming in my little panties. I came so fast.
What a mess, I soaked my panties. I wiped my fingers off on her sheets, naughty me just had to do it. Some part of me wished her dad would be doing the laundry the next day and smell me on his daughter's sheets, the juices that he himself had brought out of me.
I thought I had gotten away with it, but the next day my friend said, 'Gee you sure are a horndog!'
I said, 'What do you mean?'
She said, 'I noticed you were masturbating in bed last night.'
I said something stupid like, 'Oh, sorry I awoke the princess.'
She joked some more and I was embarassed, but then the subject was changed and we never talked about it again.
Afterwards, I was never able to look at her dad in the same way again. Every time I saw him, I imagined him with his hard dick in his hands and 'stroking it good'. I imagined him a horny old man, always jacking it whenever he got the chance alone. I developed a pretty good little crush on him after that and often fantasized about him, but the experience never repeated itself, except in my mind where it played itself out many, many times.