Agree. A "s' d" up boa doesn't necessarily mean anything. Mine do this when they are looking at something or me sometimes. Once you get to know your snake more, you will know if that means business or is just a nosy, busy, boa. Just be confident in your handling. You guys will be fine. Wait till he becomes infatuated with your face...:p
Both good points Evenstar and DooLittle.
I remember the first time handling boas. I thought the S was a sure sign of a strike. It is so different from a BP but that's just a typical boa posture.