Mary had a little lamb.
Scouting for Girls: Blue As Your Eyes
Not that it stands for anything, but medical students remember that B stands for blood transmission.
it stands for Brien that is her last name Katy brien
Bed and Breakfast...Small joints, homesteads or cabins that offer a room to sleep in and the morning meal, for a fee. I think B & B also stands for Brandy and Benedictine, a drink.