One Last Time With My Wife's Married Little Sister

My wife's little sister, Kelsey, just got proposed to by another man. And I'm ecstatic for her! But before she steps down that aisle, she tells me that her fiancé has never touched her. I'm still the only man she's ever been with, and before their honeymoon, she wants me to take her one last time, hard and unprotected, and impregnate her before her wedding night!