All three characters property of CLAMP. I just thought they'd look cute together. I drew this in an old sketchbook, I think in 2004, and found it while reorganising my (copious amounts of) drawing paper. I thought it would make a good watercolour, so did some experimentation.
The salt effect didn't work so well, but the alcohol did, except for the splatter it threw onto the rest of the picture.
Watercolours and Sakura micron pen.