When multiple people in a line rub their gentials
against the person in front of them's rear, while placing their hands near
or on said person's hips.
Another term for grind train
"Did you see the human
grindipede at homecoming
? There must
have been at least twenty-five people
in that thing!"
"Oh, dude, I got such a raging stiffy in that human
grindipede with Jessica, you don't even know..."