Touching IRN

[Jaixion]

I've had my IRN Hamish since November 2011. At first he was extremely skittish, he would throw himself around the cage and squish himself into corners even when someone just walks by his cage. Now, he'll quite happily take seeds and fruit from my hand (only through the bars, of course). I have another IRN, a 3 month old lutino. I'll be bringing him home within the next two weeks. Spending all this time bonding with him, having him on my hand and petting him makes me upset that I can't do the same with Hamish! So I'm just wondering, without breaking the trust between Hamish and myself is there any way I can pet him without scaring him? Thanks!