I'm just starting out learning Italian, so I do not know too much about it just yet. Onto the problem... In a few songs I've heard the phrase "non fermarti mai", which supposedly means "do not ever stop [yourself]", directed at singular 'you'. This phrase doesn't make sense to me at all. Should it not be "non ti ferma mai"? Because ferma is the singular 'you' imperative and it is reflected at themself (the 'you' person), hence ti.
I've also seen the phrase "non ti fermare", which is also weird. Why is there an infinitive of fermare?
Could someone explain how these phrases work? Or are these applications of 'artistic license' and thus technically incorrect, but used anyway to make the songs better? If so, what is or are the correct phrase or phrases? Thanks a lot!