It was extremely awkward being caught by his sister while he fucked his girlfriend. Erica hadn’t even known they were already intimate, and talked her brother’s ear off about the dangers of unprotected sex. Emily, his girlfriend, managed to calm her down, saying she was clean, on the pill, and that they both had never had any other partner. Erica was sufficiently placated, and began to cast her eye over her brother and the remaining bulge he attempted to cover with a sheet. “Well, you two can keep going, I guess. I’ll get out of the house.” Emily was the one to speak up. “You don’t have to go. It isn’t weird for you to be here.” He couldn’t believe what he was hearing. Emily approached him and removed the sheet, exposing his erect cock. Erica hesitated, unsure of what to do. “Go ahead,” Emily said. “He’s your brother.” Erica stared for a moment, then came to her brother’s side, a hand gliding towards his shaft. “There you go,” Emily said once Erica had taken the rod and begun stroking it. “He likes it,” she said in response to his soft moans. Emily climbed atop him and began to ride him again while Erica stripped. “Could… could I?” she said meekly. Emily dismounted and Erica took her brother’s dick in her hand, guiding it into her pussy. It filled her with every descent, and soon she was playfully bouncing on her brother’s cock. Emily smiled at first, then became bored just watching. Out of nowhere she collected her clothes and stormed out, smoke billowing from her ears. How long had it been? Neither Erica nor he could tell, but it felt right, so they continued, fucking in as many ways as there were, never tiring or coming to a climax. Just steady passion. They could have fucked forever if they were not suddenly stopped by the door opening and announcing their parents’ return. Emily never returned, but he felt indebted to her for enabling him and his sister to fuck without stigma.