When your iguana is happy(ish!) eating in your presence, and will take food from your hand, you can try stage five of iguana-taming!
Try approaching him with some food, first of all. Let him take it, but instead of taking your hand back straight away, leave it there and don't move it. He may start to lick (but hopefully not bite!) your hand, expecting more food to have 'appeared' there. Darwin did this the first time I tried it, he tried to tongue-flick invisible food from my hand into his mouth. Seeing as this wasn't working, he then 'bit' my hand - not really biting, he was just trying to pick up the food he expected to be there with his teeth, seeing as tongue-flicking it didn't work!
Anyway, just a little note incase this happens, try not to jerk or make a sudden noise or anything, as it will likely scare your iguana off!
With your other hand (hopefully before he gets frustrated and walks away!
) put another piece of food on your hand, but using your free hand that isn't in the vivarium. He should eat it if he's hungry. Keep on doing this a few more times, and then start to position the food further and further away from him but still on your hand, maybe even going up your arm! (Don't feed him too much before you want him to start coming closer to you, as you want him to come to you for the food, not him think: 'Ok I'm full now, thanks very much but coming closer to you right now is not worth it!'
If he's comfortable enough with you, and perhaps hunrgy enough if you tempt him with is favourite food(s), he should eventually be brave enough to not even think about coming to you to take the food, even if it means he will voluntarily come into contact with your hand or arm
Here is Darwin. He's already eaten a few bits of food out of my hand, so I positioned some watercress further up my arm to try and get him to voluntarily climb onto me. He did, and in this pic he is debating if it's worth getting the food:
He checks nothing might attack him from the air...
Starts to become more interested in the food again, and his focus is now on the food:
...and then finally decides it is safe enough to eat it!
(Apologies for blurry photo!!
When he's at this stage and fairly happy to sit there, you can carry on feeding him until he's had enough. When the food runs out, or he stops eating, he has a choice: he can continue to sit there as long as he feels comfortable to, or he can run straight off. Darwin decided to carry on sitting on my hand/arm for a little while this time. He's left wondering what happened, as he's no longer occupied with eating and suddenly realises he's actually sat on a human!!!
He lowers himself slightly as he feels a bit scared - iguanas will do this if they feel so threatened that displaying to whatever is intimidating them will have absolutely no effect! In such a case flattening themselves and pretending to be a 'branch' is then the best option
Neo has done this once, when my mum walked into the room she was in and she wasn't expecting it! Poor Neo actually flattened herself against the top of the chair she was on, and at the same time tried to slide around to the other side to position the chair back between herself and my mum, by extending her fore and rear leg so as to sort of hang at an angle!
Darwin takes his time to have a look around, to make sure he's not going to be hurt by anything...
...double checks that I'm not looking like I'm about to attack him...
...and then finally, he decides it is ok and nothing looks like it is going to eat him just now. I lift my arm up and towards to door if the vivarium, and I am left holding one little iguana in my hand!
I only held him there for a short time, perhaps a few minutes, before putting my hand with him on back on the floor of the vivarium to allow him to walk off if he wanted to. He walked off rather calmly and went up his log. I moved my hand to pull it back out of the vivarium, and Darwin immediately took up a defensive position atop his log!
...Just to make sure I knew not to grab him again, I suppose! I think this is purely a reaction he has developed, and hopefully he will let it go eventually