It's an adjective. It means something badass, something you shouldn't have done, describes tough situations. Its another word for sooky. It's also used to replace foul language.
Jon: Look at my new Mustang
Eric: Awwwwwwwww shucky now
Tammy: I banged Megan's boyfriend last night cuz I don't like her
Sara: Awwwwww shucky shucky
has eaten so much cock in his life his own cock has grown to abnormal lengths this "power dick" as people now know it has the power to rape chuck norris and become the NEW chuck norris
OMG GRAHAM "SHUCKY" SHUCK HAS A POWER DICK!