Randomly twist your intestines and stitch them in various places to make them appear more realistic. Spray them thoroughly with clear varnish & let them dry. This will give them a nice glossy sheen.
Place some Fake Blood in a small spritz bottle, and spritz in several areas to give them that freshly gutted look. Hang them from a torn shirt, or let them hang out over the top of your pants as though you had surgery that the doctor didn't bother to complete!