OK, I know that even my title doesn't make much sense, so here are the details of the situation:
I asked my colleague to do certain things, and he refused. So, if my boss asks why he refused, instead of saying that he is refusing to do things that he should be doing, I would say, I was was overstepping my boundaries, i.e., it is not my position to ask/request him to do things.
So, what is the friendliest way to express that idea, because after all, I'm really not asking for something big, but something really small. I don't want to blame others, but I don't want to take the blame either.
All that I want is to down play the situation. So the more informal the better. I only want to hint at this, and everyone would know what I mean in such sensitive situation.