1. To poop & go anonymously (origin: john doe); 2. a toilet crawl (house to house, bar to bar, etc.) where one partial-poops at several locations and allows a "one-sitter" to span the course of the day or evening; 3. Indiscriminate sex on a large scale with people named John, Johannes, Juan, Jan (also accepted: Jack, Mark)
Mark: "Holy shit this bookstore is awesome! That chick just had sex with 4 dudes named John and then me!"
Brett: "It's cool dude, Mark is also accepted."
Mark: "I guess that's why they call it a Johnny hop!"
(Mark & Brett hug)