First I would like to clear up that flesh
tunnels are not "the tunnel of flesh created from stretching your ears." Creative boys, but wrong.
Flesh tunnels are large (or sometimes not so large) tubes that are placed through large stretched piercings. Most commonly, they are placed through earlobe piercings, but may also be worn in
nipple piercings,
frenums, hood piercings, tongue piercings, or practically any larger piercing. source: bmezine.com