You can transport him in a deli cup or tupperware/gladware container with small holes punched in the top or the sides. Or, you can put him in a small critter keeper. I have had several male leos whose bulges get large. They went to the vet and needed some very minor surgery to take out what I think is a buildup of sperm. This sounds really gross, but I regularly squeeze these guys' bulges to get out the sperm plugs. They've been normal size since I started doing this.