The adverb wackily describes anything you do in an exaggeratedly silly way. Everyone at the circus will laugh at the way a clown wackily attempts to climb a ladder.
A truly ridiculous, goofy tv show might be described as wackily humorous, and you and your cousins might laugh at the way your grandpa wackily juggles kitchen implements. If someone's wacky, they're funny but a bit peculiar or over the top — and behaving wackily means acting this way, like a comedian doing pratfalls or a class clown making everyone gasp and then laugh out loud.