We're at a party together - the three of us. I've noticed that you two have disappeared. I go looking for you. I open up one of the bedroom doors and there you are going at it hot and heavy on the bed. I quietly slip inside the room and close the door behind me. I'm so turned on watching the two of you. Leaning back against the door I slide my panties down to my knees and lift my dress up to my tits. I begin rubbing my pussy. I rub it harder and faster. Finally I can't take it anymore and cum. I pull my panties back up, adjust my dress, and quietly slip back out the door without ever being seen.