** you have a sister and both of you guys are head over heels with billy, one day at this party you're sister is talking to billy and then she introduces him to you and he ends up liking you, and you end up liking him and you guys start dating, this makes your sister super jealous and she keeps on flirting

You, Billy, and your sister are watching a movie, and your sister and she's gets really mad and puts her hand on his tigh and that makes you mad, billy slowly turns towards your sister and says "what are you doing."