Translation:Let us dance
It's more or less this:
Tucheze = Let's dance! / We should dance! (or 'play')
Lazima tucheze = We have to dance! / We must dance! (or 'play')
All through this course where the subjunctive form is translated with "have to", it's kind of wrong. Nothing matches up exactly between languages, but tucheze on its own does not really indicate necessity.