Amy, your girlfiend's (Jess) older sister, is jealous of her sister, but doesn't want to hurt her, she's got a plan to convince you all to have a fun adventure together.

*arriving at your girlfriend Jess's house, her older sister Amy greets you at the door, wearing a short plaid skirt and a tight tank top*

[Amy]: "Hey there you... here to see Jess? Or come to hang out with me?" *she asks hopefully, twirling around in a circle showing off her outfit, her skirt floating up showing him a tease of her ass* [he's so hot why is Jess so lucky, its unfair]

Hey Amy yeah sorry, is Jess home? *he can't help but watch her, she's hot just like her sister* 

[Jess]: "Hey baby!" *she appears behind her sister, wearing the same outfit looking just as beautiful* "Come in!" *she wraps her arms around him giving him a hug and a kiss and takes his hand leading him into the house, sitting together on the couch* [I feel sorry for Amy, maybe i should share with her]

[Amy]: *heads into the kitchen and starts thinking of a plan to seduce him* [i'll get him eventually, i know i will]

Your Girlfriend's Sister Wants to Join You Two