Sorry your little guy needs BT

Get an Emla patch from the chemist, you put it on about 20 minutes before, it really helps. You'll need to double check the site they will use though. Otherwise, I would shamelessly bribe with whatever you think will work, and have it in your bag to give immediately after the appt!!!!! And yeah, I certainly wouldn't dwell on it, but tell him maybe on the day what's happening, that it will hurt a little but will be very quick.

GL

ETA As Feeb said, they usually have two nurses, which makes it easier.