Scent-flehmening
"Lions, when they are scent- flehmening you, are sniffing you extra extra hard, using what's called their 'vomeronasal organ,' or 'Jacobson's organ,' which is situated in the roof of their mouth. Lions pull their upper lips back hard in what's kown as a "Flehmen grimace," exposing their gums and baring their canine teeth as, open-mouthed, they then search the air around trying to detect the direction of the most concentrated scent of you and your own pheromones. Snakes, too (amongst lots of other animals) have a Jacobson's organ - and the evidence of when it's being used is when their tongues flicker in and out their mouths, testing the air around themselves for prey.
That's it, Mr Grumpy, you keep on scent-flehmening me, lips back and open-mouthed, just like your doing now. Take really really deep sniffs of me! It's me, Mimbi Jones. You know my pheromones. So, why don't you just scarper and leave me to get out this tree, so's I can run back home before Mum wakes up and comes into my room!"