Context: A child is preparing his props for a play. My first guess was that this was a variant of ちょっと, but I tried double checking on Google and got really weird grammar details that don't match the context.
(Converted from an earlier comment on encouragement from @naruto. 😄)
I suspect that this is just a variant of the よいしょ call, basically kinda like "heave, ho!" in English, something said where the よい part is the windup, getting ready for a strong effort, and then the しょ part is where the person applies pressure / throws something / pulls hard / etc. If you can read Japanese, here is the よいしょ page at Kotobank.