Look at my girlfriend, she loves to fuck

My sister wanted to learn how to fuck, so my answer was quite simple: Learn from my girlfriend, she loves to fuck. After that comment I invited her to watch me fuck my girlfriend so she could learn from what she does. At first she seemed quite uncomfortable but little by little she enjoyed it and realized that yes, my girlfriend, she loves to fuck me and feel my cock inside her. No doubt from today my sister will have a new concept of me and my girlfriend, I’m worried that now she wants to try my cock.