Milk Swap

One big, mesmerizing moo from Brian's prized dairycow and I wind up feeling very strange indeed.  I soon realize that its powers have been transformed to me, but there's only one way of proving that to Brian.  I show him my new power and he's blown away.  He wants to taste it and he's not prepared to stop there!  Empty me, Brian, and give me that big, hard thickness!