NYH-051 Counterattacking my sister-in-law's teasing panty flash with a spanking and deepthroat! Payback with intense piston sex

My father's new wife brought along a stepchild, and I, who was an only child, gained a sister. This sister has a cute face but is a little devil, always showing me her panties through her super mini skirt and enjoying my reaction. When everyone was out, I snapped after being called a 'coward.' I pounced on my sister and spanked her ass until it turned bright red. She had a face that looked like she was about to cry but was actually excited. This bitch is a masochist. I tormented her vagina with vibrators and electric massagers, and made her deepthroat me. Of course, the sex was intensely piston-driven, making her cum over and over.