That One Time I Crossed the Line with My Sister-in-Law's Secret Intimacy Toy

I've been in my long-term relationship for over twenty years now. We've always been open and honest about our desires, but there was one time when I couldn't stop thinking about a certain toy that belonged to my sister-in-law during her last visit. It was something different from what we usually explore together, more intense, electric, designed to shock and excite in ways neither of us had ever experienced before. After she left, I secretly used it on myself. The feelings were overwhelming and exhilarating, but I felt ashamed because it wasn't something I could share with my partner at the time. It's like a secret door opened in my mind that night, one I'm not sure how to close again.