I’ve never used Simon Says in my Latin classes because I’ve never liked the Latin it tends to produce. The teacher says something like ‘Simon dīcit “tollite manūs!”,‘ but it doesn’t work for me grammatically.
You could say ‘Simon iūbet vōs manūs tollere‘ or ‘Simon vōbīs imperat ut manūs tollātis,’ but then you’re far beyond the target audience.
To give the command in a direct quotation you should use inquit, after the commander’s words. And why not make the commander Quintus to effect some kind of alliteration? (While inquit Quīntus may sound harsh we should be driven less by euphony than by the demands of the sounds and structures of the language.)
It might go a little something like this:
tollite manūs, inquit Quīntus!
nunc, salīte omnēs!
ah! nōn Quīntum dixī!
And a translation:
Simon says, “raise your hands!”
Now, everybody jump!
Ah! I didn’t say ‘Simon’!