My stepdaughter spends ages on the toilet when she poos and I love to go in after her to enjoy the smell and the warm seat where she's been sitting there so long. She leaves it un flushed and the sight of all those big turds is such a turn on. I've always wanted to her to do it in her knickers and one night I picked her up from work and when she got in the car she said she was dying for a crap. I started to get hard and asked her if she could make it home. She said no and my penis grew so hard it ached. She noticed the tent in my trousers and lifted her bum off the seat to push a huge turd into her knickers. She sat back down squishing the poo all over her bum and it exited me so much I creamed my pants. The smell of her poo mixed with the smell of my cum soaked pants was awesome and as soon as we got home I let her clean up in the bathroom whole I got hard again. As soon as she finished in the bathroom I went in and saw her soiled knickers on the floor. The toilet was full of her poo and the seat was warm so I guess she hadn't finished in the car and left the rest for the toilet which added to my excitement. I picked up her dirty knickers and wrapped them around my penis getting her poo all over it. I slowly rubbed myself off untill I came into the gusset. I washed myself clean and came out of the bathroom leaving her knickers on the floor where I found them.