After moving away and finally not needing to hide their relationship, a brother and sister go out on a proper date and run into someone from their past. She'll keep quiet, for a price.
His wife sent him to pick up a mattress that she had purchased. He found the mattress and a sex-starved teenager who showed him how smooth and comfortable the mattress was. That session made him late to collect his sister from the bus depot. She tasted his pussy smelling lips (no time to wash his face), and helped herself to his still sticky cock.
He and his wife of thirty years were in a shoe store with her trying on various styles. He spotted another lady trying on his favorites - strappy high heels. A conversation develops, and he volunteers to help carry her purchases to her car whilst his wife heads to the nail salon. He invites the lady for a tour of his motorhome parked near her car - especially a grand tour of the bedroom.