Homemade, fucking my stepfather's girlfriend while he rests in his room

My stepdad's girlfriend is staying in my room and starts telling me she really wanted me to fuck her. As soon as she sees my penis, she immediately mounts it. I want to go harder, but I can't because we don't want anyone to hear us. She begs me to go harder and starts moaning louder. I cover her mouth, slap her, and keep fucking her until I come inside her.