My mom's caresses with her feet

I rarely get to be alone with Mom at home because my sister is almost always there too, but sometimes we find moments to be together. Sometimes at night, when my sister locks herself in her room, Mom and I have a hot and secret game. We sit on the living room sofa to watch a movie. She leans back and puts her feet on my legs, covering herself with a blanket from her waist down, covering all her legs and feet. Under the blanket, Mom starts caressing my penis over my pants with her feet. This way, if my sister comes out of her room, she wouldn't see anything unusual.

Sometimes during the entire movie, my sister doesn't come out of her room. She asks me to take my penis out of my pants and rubs it with soft caresses using her bare, warm, and sweaty feet until she makes me ejaculate. I squeeze her leg twice when I'm about to explode, she already understands the signal and peeks out from under the blanket during my orgasm to see me cum. The scent of her sweaty feet makes me gush like a fountain, covering them with my cum. I love hearing her whisper “oh my god that's beautiful” when she sees me spilling on her feet. After that, she smiles flirtatiously at me and continues watching TV and rubbing, spreading all my semen on her feet until it's all absorbed. When her feet are completely dry, she just gets up and goes to sleep. We never talk about it, as if nothing happened. It's a rich and silent game we have some nights.