Jerk off on her face
From Create Your Own Story
You begin jacking off in earnest, looking down at your pretty little sisters sleeping face, imagining her mouth dripping with cum. It doesn't take long for the image to send you over the edge, and aiming your cock head towards her nose and upper lip, you spray the first strand of semen onto her cheek, before unloading several more ropes of cum onto her mouth and chin.
You heart stops in your chest for a second as she flinches and mumbles something in her sleep, but she doesn't wake up.