nerding is a form of studying which involves more of mugging but in most ways it is used as a slang to transpose the word studying. this term coined in National Public School, Indiranagar, Bangalore (where else) is often used as a way to chide others for doing the same.
"What are you nerding?"
guy to another guy studying : dude you nerding for the test?
guy1: Dude, the test is today man! I'm dying!
guy1: Chill man, You were nerding the whole night. Why are you scared?