Step Mommy Rides Out the Zombie Apocalypse

Custom request, no names used: "stepmom and stepson were at a pool party when a zombie apocalypse just started and now they’re trapped in their house. while the stepmom is trying to figure a way to survive she notices her stepson just staring at her ass. so to stop him so he can focus on more important things the stepmom first starts bending over to let him masturbate to her ass so he cums but when that doesn’t work she rides him reverse cowgirl until he creampies her. could you also incorporate sph if you can?"