Are you getting paid?

-"yes": Yes, it is a job.

-"no": No, it's not a job.

I guess.

Forgive me but I just don't understand the question.  Might you please elucidate?

It depends on your contract. For visa purposes it probably does not matter because the people you're working for are taking advantage of you so they are unlikely to complain.

Loaded question.

Teach what?  English? Sure, go ahead as long as you aren't receiving compensation that could be considered taxable income or promotion for a for-profit business. There is usually no problem having an "English Corner" or something like that.

"Another testament of the lord Jesus Christ as told by the Book of Mormon"? Prepare to get a plane ticket home and a ban on getting another visa to return.

So again, teach WHAT?