Romantic Dinner with Sis

Your girlfriend is sick, meaning your birthday dinner was cancelled, so your sister decided to make you two dinner and try and salvage the night for you. She's always been so sweet. You two have always been ultra-close, except lately, with your new girlfriend around so much, you two don't see eachother as often. So its nice, in a way, that your plans got spoiled. Your sister seems to agree. She's really excited about your little night in together. Maybe more than excited? Her outfit is, honestly...well, you hate to even admit it to yourself but...it's sexy. Low cut, tight, showing off her best assets perfectly. She must know she's pouring out of it, right? "You know we don't spend time together anymore," she says, leaning across the table towards you, pushing her gorgeous, full tits together as she does. This can't be on purpose, can it? "I know she's your girlfriend, but can't I give you that sort of...intimacy?" You're not sure what's happening here, but you know that your cock is starting to stir in your pants, and your sister is noticing. She's practically licking her lips! "I have a confession to make," she says, getting even closer...oh god, are you really going to do this?