Ciao a tutti!
Incontenibile/irrefrenabile is in my opinion the word that best translates the idea you ask for. Irrepressibile is definitely correct (and would be the closest to the meaning) but I'm afraid it's too rare. Just to give you an idea: I never heard it or saw it written also if it absolutely makes sense.
Irreprimibile would be a perfect choice when talking about chocolate or generally something you desire, as in the example; we mostly use it to talk about a sensation, something personal or that comes from inside. It's correct but in my opinion it wouldn't be appropriate the same when talking about a living/human being.
Ciao, hope it helped!
Typo-alert!!! Alfry scusa se sono invadente ma faccio notare il typo perché potrebbe confondere chi non è madrelingua... irreprensibile doesn't translate the same as irrepressibile.