If you're nervously going to pick him up and taking a while to get hold of him he might be seeing you as a threat and defending himself. I had one that was a bit *****ly to get hold of so I used to pick him up carefully on a small hook about 12" long then gently get hold of him at an appropriate moment. Also make sure you don't smell like food/mice - make sure you wash your hands before you handle him.
cornsnakes, ratsnakes, bullsnakes, boas and day geckos Location:Leeds/York/Selby area
all good advice so far and just too add, make sure you go in to pick him up confidently, i usually go straight for the thick part of saphy's body and although she sometimes coils up if i go straight in with out hesitating she is fine