speaker humping

A behavior practiced by some hardcore techno enthusiasts in Los Angeles at rave-style events at least by the mid-1990s, though it possibly originated a few years earlier.

Physical act resembling sex between a human and sound equipment consisting of bumping and grinding bass bins, mid-highs, or other hip-height sound reinforcement gear.

"Did you see those kandi kids speaker humping?" "Yeah, they practically knocked down that stack, they all were bumping into it on the beat. But that wasn't as crazy as that mosh pit got."