I lose control and fuck my sister-in-law and come to her in her mouth, after she rides on my cock

I see her every Saturday at the building's swimming pool. Black swimsuit, dark glasses, tanned skin that glows in the sun. Her ass is huge, round, moving with a gravity that attracts the eye every time she walks up the stairs. Today I am left alone in the water. She takes off her glasses, looks at me, smiles with a crooked corner. He swims closer, leans on the edge next to me, his legs brushing mine under the blue water. He asks me if I live alone, I say yes, he nods as if that was the answer I expected. He asks me to pass him the towel. I follow her to the elevator. As soon as they close the doors and he's already against the wall, he grabs the back of my neck, kisses me with an expert tongue that knows exactly what to do. He pulls down my swimsuit, kneels, sucks me with a mouth that has had years of practice.