Bonobo Tongue Kissing
The only other species besides Homo sapiens that engages in tongue kissing is the Bonobo (Pan paniscus or Homo arboreus). Bonobos, in fact, engage in it even more commonly than humans. Even juvenile males french kiss each other in-between bouts of rough-housing. Some Bonobos have even given tongue kisses to humans (in zoos, not in the wild).