Our cat Lilly has begun in the past few weeks to let her tongue stick out of her mouth when resting. At first we thought it was cute, but now I am wondering if it is tied to her health. When resting with us on the couch she come purr with her tongue just slightly sticking out of her mouth and begins to drool just a little. She also shivers just slightly as well. Not anything extremely noticeable, just a slight shiver. I can't tell if these are just habits and she's happy to be around us or if something might be wrong. She is eating and drinking normally, isn't vomiting, everything else seems normal. Any thoughts?