Step-daughter, knickers and paste...!
My very cute 19 year old step-daughter wanted her room redecorating so I was only too happy to help get stuck in with her.
We stripped the room together, with me mentally stripping down her little size 8 frame of course, and then she left me to it for a bit while she went out on an errand.
So left alone with her room, I did what I often do when given the chance, and had a play with her knicker drawer! The feel of her small lace thongs soon had me hard so I wanked with them, the feel of the lace and silk on my cock, knowing they were hers had me throbbing and ready to cum ..at which point a naughty (naughtier?!) though hit me....so I shot my load into the wallpaper paste, put the knickers back (carefully so no cum went on them!) and used the cum laden paste to stick her new paper to her wall!
Knowing my cum is on her walls when I talk to her next will no doubt raise a slight smile on my face! ;-)