You've confided in your older Step Sister about how your wife has let herself go and the sex has dried up. You just aren't attracted to her anymore. It's your Birthday and your sweet sibling wants to make it up to you with a blowjob. She immediately gets to work, sucking it sloppy while talking dirty and putting down your wife. She even pulls her round ass out of her yoga pants to slap with spit. Then she milks you until you cover her face, like a good girl.