Putting any transferable pigment (e.g. eye shadow, slow drying ink, or face paint) on your thumb then drawing a line across a victims forehead whilst shouting "Simba".
1: So yeah i went to see the Lion King 3D it's really good
2: Oh? Who's your favourite carachter?
1: Probably Rafiki. Yours?
2: Mine's definitely *rubs thumb across forehead* SIIIIMBAAAH!
Prime example of a real life Lion Kinging
Lifting a small animal or child into the air and singing the circle of life, preferably with some sort of light shining on you, like rafiki does to simba at the start of the lion king.
Girl 1: dude, if you do don't stop lion kinging the cat, she's gonna scratch your eyes out.
Cat: Meeeoooowwwww *scratch*
Girl 2: I deserved that
When you nuzzle into someone, (generally into their neck) in a cute and slightly atavistic fashion, much like employed by Simba and Nala in the popular Disney film, "The Lion King"
Hannah; What are you doing?
Rhiannon; Lion King-ing you. What? It's cute!
When you hold your phone up in the air looking for a signal
"I was in the middle of nowhere lion kinging my ish tryin to find signal!"