[Noodles]

The first issue that needs to be addressed (besides the possible stone/urinary infection) is a larger cage. I know you're waiting for your coroplast, but is it possible to make a temporary "pen" using grids and some towels w/ maybe a tarp underneath? While it's great that you give him floor time, having a large cage is essencial for exercise and well-being.

The next issue would be getting him a play-mate, and it sounds like you're doing that already, which is GREAT. Using a large "pen" w/ grids as a temporary cage like I mentioned above will also allow you to easily separate the two pigs until Hot Wheels is neutered. I think having a friend for him will help A LOT with your problem. From my experience, piggies are much happier and more comfortable with a friend during play time. When I had only one piggy, he loved lap-time, but didn't do much during floor time. Adding a friend gave him a chance to play games and have company as he explored his surroundings. Make sure that your floor time is in a safe area and provide plenty of hiding spaces, obstacles, tunnels, and things for your piggies to do. Also, put out their food, water, and hay while they are having floor time and play hide and seek with their favorite veggies by scattering them in different areas to get them moving and munching happily.