[tlhIngan Hol] To -choH, to -'eghmoH, or to nothing ?

In imperatives, sometimes we see in Ca'NoN {-'eghmoH}, and sometimes we see {-choH}. For example: {yItam'eghmoH} or {yItamchoH}. I don't know, if there is a Ca'NoN example of using just the verb, e.g. {yItam}, but regardless whether there is indeed such a case or not, I wonder.. Should anyone choose whatever he likes ? Is there something of the three (-'eghmoH, - choH, or none at all), one should necessarily use in an imperative ? Or do we just use the Force ? ~ changan qIj