Fucking your Pregnant Sis before her (Shotgun) Wedding

My bachelorette party is tonight and I need help picking out a dress that fits. I got knocked up so nothing fits right, but I trust your opinion so I start showing off some dresses. You start getting touchy feely and it progresses to you groping me and things heat up. You're my step brother we really shouldn't be doing this.. what if we get caught? I tell you to lay on the bed and I start rubbing my pussy on your cock.. just the tip won't hurt right? Before we know it your whole cock is inside me and I'm bouncing on you, then we switch to missionary and doggy and you creampie me!