Like John said, you have to read them, even the most placid ones can get testy.
Yes breeding season can bring out the worst, has he been eating? I've also seen it in one of my BCI females where "normal" food intake was not enough and she got aggressive until I was giving her a little more.
One thing you can do that might help is leave one of your dirty shirts in his cage to get him more used to your scent. Dirtier the better
Lastly, is he "hook trained"? Meaning you go in with a hook or other item and touch his nose to let him know it's not food time but handling time? Have the nips been as you were reaching in to get him out?
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Thanks,
Dave Colling

www.rainbows-r-us-reptiles.com
0.1 Wife (WC and still very fiesty)
0.2 kids (CBB, a big part of our selective breeding program)
LOL, to many snakes to list, last count (02/01/2010):
42.61 BRB
27.40 BCI
And those are only the breeders 
lots.lots.lots feeder mice and rats 

