Sandy took her right hand out of the horses head, snaked it around behind her, slid it between us, and grabbed on to what was poking her in the butt. ...ow I'm quite sure she thought it was going to be part of the costume. I mean I don't think she knew she was going to end up holding her twin brother's cock in her hand. It was almost comical. She grabbed it, froze, squeezed it, let go, moved her hand around from side to side, like she was trying to figure out what else was nearby, and then slid. The 'soap' that he had used to bring himself off was slowly pooling, moving from individual strands into a mass around the base of his penis. From there, small tendrils were extending up his cock, moving quickly toward the head. Even as Cord started realizing that something felt wrong down there, the first of the tendrils reached the opening at the top.Startled, Cord jerked his head up and stared down at his crotch. Just in time to see the first of the tendrils bury itself in his penis.. This sensation made my cock swell and I felt a warmth growing there. I found myself in a semi erect state with the shaft rising a little and my cockhead felt swollen and full. I could feel them looking not necessarily in a sexual way but with a full gaze, taking in my entire body as artists. This did not diminish my state of arousal though. I continued to assume a variety of poses, each about 1 minute or so for their drawings. After 10 or so poses Lucy directed me to break, which was a relief. Her arms and shoulders went limp, her feet dragging on the floor uselessly. The indefatigable Reiko had finally exhausted herself, her body a limp rag doll as I mercilessly pounded into her. And then her gasping stretched out into a long wail, ending with a whimper as her body exploded with pleasure, her limbs tensing up one last time as the orgasm rushed through her body.And then I finally let myself go, growling as I fired the stored up loads that had been building all night, emptying myself.