Many have said in this thread that they become annoyed when a student attempts to teach them. I've been thinking about this topic quite a bit lately. In a previous post on this thread, I related my experience with a fellow student attempting to teach me, and my annoyance at this. I began to wonder why it was that when he told me things that would help my technique (which were very good points now that I think about it, and have made my throws more effective when I incorporate them) that I became irritated with him, while others may teach me on the mat and I accept their advice with interest and gratitude. I think now that it is intention behind the comments that may make students teaching other students a good or bad experience. In the case of this particular student, he gave me tips not to help me become better at technique, but used them as an opportunity to point out what was wrong with my technique and to prove that he knew more than I. If the intention of on-mat student-to-student teaching is to help and improve, I think that it can be very beneficial (even if their comments are "wrong," if said with good intention, it is much less irritating than if they had said it to prove that they were smart), but there are "helpful" students who are just trying to feed their ego. While I am rather glad that he pointed these things out to me now, I can also see how this kind of attitude could ruin otherwise helpful advice.