Optional direct object?

Hi. Is it correct to say a direct object is not necessary like one below where the context makes it clear what the verb refers to (see the word in bold letters). Let's say there's a person who has just enrolled in a karate class and learning to do a side kick properly. Are both of these correct as what the instructor might say to that person before showing him or her how to do the side kick properly? Thank you in advance for your help.

"Don't do like that."
"Don't do it like that."