How do I make a bong in my ceramics class without my teacher finding out?

I made a mug with a face on it, the mouth was slightly open. There was a hollow tunnel from the top of the handle, down the side, through the bottom,  and to the mouth. Quite complex, but also well hidden. After the final firing everyone was congratulating me and the instructor came over. He looked at it, and said it was very imaginative and well made. I got an A on it. Another guy tried it and got glaze poured into the stem by the instructor. 

Most instructors are not as stupid as you seem to think,  Make your bong is a style that does not look like ever bong that can be purchased in shops.

You can't.  It's not that cool a thing to do anymore,  it's so cliche now it just comes across as childish. 

Build a little "hideaway" in the corner out of any spare materials lying around, such as cardboard boxes and old T-shirts, and make the bong in that. To ensure the teacher doesn't intrude simply hang a sign outside which says "No Teachers Please". When completed, you can find out how to actually use the bong by looking at Youtube videos or asking one of the cool, popular kids. Hope this helped.