Please Go Ahead

What is the Japanese phrase for "Please go ahead" or "After you"?

お先にどうぞ。

I have not been reading anything Japanese for a long while. Work has been crazy with non-stop meetings and presentations. Next 2 weeks, I have to teach a study group of about 20 people at work on 2 chapters of wireless technology. I am not going to prepare any Powerpoint slides but just use the book and go through all the important concepts. My teaching style has always been super fast and efficient, tailor mostly to the sharper or well-prepared people in the group. I don't allow slackers to hold back my class. And it is usually through these kind of teachings that I differentiate the diligent and smart ones from the crowd. And that's how I end up picking them to work on my projects, whenever possible.

Yes, I realize I am a very bad teacher. Completely biased, impatient and always have high expectations...