I don't think it's much of a secret that I LOVE SPANKING, and you wrote this one so well; I totally squeed at the image of Lavender across Santa!Neville's lap. Also, the dialogue was perfect, Lavender is wonderfully bossy (ooh, bringing up Augusta in order to manipulate Neville into giving her what she wants!), and I love every Wheeze that ever Wheezed, your Santa-baby hat certainly included.
Delightful! Thank you for sharing!