As a birthday gift for Vulpine, I got him a magical spray to be used in Team Fortress 2 (you can get them here), where the state of his diaper changes from clean to used depending on the viewer's proximity to said spray. I wasn't sure if he preferred it to change to wet or messy, so I got him one of each! I was pretty sure he was going to like that pretty, pink, frilly dress though! Goes well with his long, girly hair.
Of course, now I'm a bit jealous, since I want a spray like this too! Except without the dress mind you, and with about 20% added coolness.