nah, "đang" is for the present continuous (or 'progressive') tense - an action that is currently in the process of happening. it always uses the form '-ing'.
however the form '-ing' isn't only used for that tense. it is also used in a form that is basically equivalent to the infinitive: "likes drinking" is essentially the same as "likes to drink". so the original poster is right, it should be accepted as equivalent