'Sho o suteyo machi e deyou' ('Throw Away Your Books, Rally in the Streets'), dir. Terayama Shuji, 1971. (Japan, R2 NTSC).

I love this shot. The cameraman puts down the camera and then lights up a joint with some school-kids. People in the background stop and stare through most of it.

The sign the kid is holding says "If you feel angry, punch this". And yes, the punching bag is a big old cock.
Image from a Robert Crumb comic that Terayama inserts into the film. I wonder if he got the idea from 'Scorpio Rising', which was a popular film at one of the ATG theatres. They even named the underground theatre after the film (Sasori-za).