[LottiFurmann]

When I first read your post I was really upset. At my dojo we really focus on the sempai/ kohai relationship all the way down the line, not just with ranked students. If you've been to class twice, you're expected to help the guy who's brand new today. Even if its only in the simplist things, like where to line up, or what way to bow. As far as teaching vs practice, we need to always keep in mind that if we don't teach, we won't have people to practice with. I'm honored to help students out, and if they don't know what they are doing it reflects poorly on me so I take it very seriously. Not to mention I really enjoy seeing that moment "when something makes sense" to them.
We always save time at the end of class for practice too. It's good for the new students too watch every thing applied to practice. So don't feel bad about them having to teach you, just remeber to be a better instructor when you are asked to teach.