"This is not cheating, right?" My girlfriend's older sister, after realizing I'm a virgin, keeps coming on to me one after another. Honestly, her older sister is incredibly beautiful, and I can't help but be drawn into her charm. I do have a girlfriend, so I'm genuinely torn. But the older sister says, "Going all the way is cheating, but just the tip is fine!" Treating it like a game level, she teases me by rubbing her pussy against the head of my cock, playing this provocative game over and over. Behind my girlfriend's back, we sneakily repeat the act of barely inserting it in different places. Is this cheating...? (sweating)