Felt Up

My wife Jo and her older sister Jera (33 and 35) look very much alike. Both about 5 foot 2, average build, thick ass, shoulder length brown hair, you get the point. Any who, I walked into the spare bedroom where they we're going through some boxes, both bent over looking down, and all I knew was I going in for a hand full of ass. I stepped between them and put my hand on the back of my wife's leg and slid my hand up her shorts until my fingers where in her ass crack with the tip of my middle finger giving her a little poke in asshole. It was at that moment she turned with wide eyes, and by she I mean Jera. I realized my mistake but she said nothing so I slowly withdrew my left hand and slid my right hand up my wife's shorts and did the same. My wife reacted! She jumped and smacked my hand away and gave me that "not in front of my sister" look. It's funny to think about and I'd like laugh about it with them, but knowing my wife she wouldn't laugh, she'd just be pissed off and jealous. It'd be even worse since neither of us told her about it when it happened.