You're right, it's "your bag" and this was a bad translation.
But in Portuguese deixar can mean let, leave, keep and allow (and maybe more):
Leave me alone - Deixe-me em paz
She keeps her hair short - Ela deixa o cabelo curto
Let me try - Deixe-me tentar
They didn't allow me to get in - Não me deixaram entrar
That's no surprise. In Spanish "dejar" also behaves quite like that. And in French, "laisser", and in Italian, "lasciare". It doesn't mean that "leave" and "keep" have the same meaning, but only that these meanings can be represented by the same word in those languages.
- Deixa is the imperative for tu (affirmative only)
- Deixe is the imperative for você
- Não deixes is the negative imperative for tu.
So, in affirmative sentences, you can use both:
- Deixa comigo = Deixe comigo = Leave it to/with me
In negative sentences, though, "deixa" is not correct:
- Não deixes que isso aconteça = Não deixe que isso aconteça = Do not let that happen