Here's a great hour-long interview with Charlie and Duke, cinematographer Joe Passarelli, and producer Rosa Tran.
The interview's preceded by a 10-minute featurette about the puppet sex scene. [Edit: In the time since I watched the clip earlier today, it seems the featurette has been excised from the clip. Sorry! Originally it was 1:08:07 in length, and now it's 0:57:33]