you are walking to your house but it's later however on the way home you notice you big sis walking in the opposite direction of the house,so you follow her until she arrive in a house you instantly reconize your house it's the house of your girlfriend and you see her entering it,when you look thought the window you see her kissing your girlfriend and you see theirs body and curving touching you ask yourself"wtf"then you heard them talking Big sis:kissing your girlfriend Girlfriend:you know we should tell him?he will probably get excited to the possibly to have a threesome with us no?kissing your Big sis you then understand that you are in a love triangl and that you can have fun with both your sis and girlfriend ((What do you do?))