Sorry people - I think you're getting confused about the dialogue in "Beast of Burden"....
Yes, the torture stick is used in that episode, and the term "firestick" is also used.
But - it's used by Burrock to describe a staff weapon, when he finds that the P90 he's stolen from Jack empties after shooting a full clip at the caged Unas. He comments that the gun is effective, but not as good as a firestick since it runs out (of ammunition). {Or words to that effect.}