Do anything in a humorous, playful way and you do it jocosely. If your uncle is chuckling jocosely when he says you're in big trouble, you'll know he's joking.
Jocosely is a formal way to say "jokingly." Use this adverb any time you want to describe an action that's done in a facetious or satirical way. You might cheer everyone up at dinner by jocosely imitating each of your teachers, or jocosely offering restaurant-style reviews of the food you're eating. Jocosely shares a root with joke, the Latin iocus, "joke, sport, or pastime."