My Sister, The Princess

Athena (Fleurs) and her stepbrother Robby (Echo) are dedicated to squabbling with each other, introduced in a nasty argument in the kitchen one morning. Living uncomfortably together under one roof after the marriage of her mom to his dad, they seem to detest each other, until the conversation turns to sex.
After he's caught staring at the blonde beauty's body, and getting criticized for it, Robby explodes: "You're such a narcissist! You're exactly the type who thinks every man wants to fuck her". "Most men do", Athena calmly replies. "Right. How about my dad, my hopelessly in love with your mom dad, wants to fuck you?", he asks. Athena nods Yes, smugly. "Okay, how about me, do you think I want to fuck you?", Robby adds. She walks up to get very close to him and says: "You don't?", to which Robby erupts with laughter. "I can't believe I'm going to be late because I've been arguing with a dork", she says, condescendingly, and leaves, giving him the finger and insulting him once again before she leaves.
Later, Robby finds her crying on her bed, but he's still resentful for her princess-like behavior. Her tears quickly wear him down and he apologizes. "Is everything okay?", he asks. "No! I hate my job, I have no friends", she declares, whimpering. She pulls on his heartstrings. Robby is a good guy and hates to see his sister cry. She's annoying, but he loves her.
He sits on her bed next to her and tries to build her confidence, but she says: "I don't need your pity". They both make confessions: she admits to having an obsession about sex, while Robby admits that after at first being intimidated by her beauty when she first moved in, later he's developed a crush on her. When the issue becomes siblings having sex together, the mood warms, and Robby concedes: "Maybe a kiss would be okay?".
"A platonic kiss, no fucking", she whispers. Their kissing more than breaks the ice, and soon they're exchanging friendly insults, born of sexual heat rather than anger. "Show me how much you want me", she murmurs. Covering her with kisses, Robby goes down on her, moving her panties off to one side to begin licking her pussy. He removes her bra, revealing beautiful, natural breasts. After a sensual blow job, she asks him: "I want you to be my first. Please be slow". Watch the taboo scene slowly escalate into passionate sex...