my stepsister doing exercises and ends up her really hard until she cums nice 1PT

While my stepsister is doing her exercise class, my stepbrother looks in the mirror and realizes that she is getting very fat, and asks me for help with the exercise, and while I help her with the exercise, my stepsister gets very horny and asks me to fuck her with my huge penis until she fills her face and breasts with a lot of milk.