I'm pretty sure the hairball is his fecal matter. I'm new at tegus but I live with my buddy Zack who I think loves pain but he has many methods that works for the pain tolerating person or for the person who does't like the artery squrting method.
1)One of his methods is he will sleep with a cloth bag (pillow sheet, reptile breathing bag that fits the animal comfortably) to get his scent on it and then when he wakes up the next day he puts the tegu in the bag. He will drive places being were in hickville and nothing is close by or check his email with the bag in his lap. Do watch out for when your tegu starts releasing him or herself (try sleeping with a few bags so you can throw the one bag in the wash while you do mthe switch. The idea is to get the animal used to your scent and to be comfortable with you and try doing this untill you notice the difference on how much calmer the animal is or try a week or two of this every or everyother day.
2)This is what he normally does he just picks up the animal in a way to try not to get bit put your right hand under ferosious belly with tail on your right side under your arm between your elbow and arm pit and hold tail there. Then with your left hand loving stroke ferocous's head and body. And when he shows you his mouth lightly close his mouth by using your left hand in a petting fashion. Try using your pionter and middle finger to pet the under the jaw and at the same time use your thumb to pet the top of the head start the petting at the base of the head to the end of the nose do this or just pet him on his head or under the throat. What this does is show the animal your not afraid and that him trying to bite you is usless. If you ever get bit try not to put the animal down or back in the cage for at least 15 mins b/c doing so shows the animal that any time they decide to bite you it doesn't mean they will be freed. Of course if you get a bad bite please put the animal down and use alcohol or what ever you prefer for the wound and rap it up tight. If you do have to put the animal away after they bit you please pick up and hold the animal for then 30 mins as soon as your able to.
These are methods that have worked wonders on iguanas, tegus, snakes (a little different methods but about the same), savannas, nile monitors.
Always keep in mind if you have a colombian tegu then it may never tame or tame as well as you want it to tame.
I hoped I explained well enough for you and if you have any more problems I will do my best to help and even contact others if needed so I can pick at thier brains.
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