When you're discussing something geeky very intensely.
When you know a lot of information about something unusual, usually nerdy, and express it with great enthusiasm.
Bruce: Batman never killed his villains until Robin died, which is the onlyreason why people began to call him 'The Dark Knight'. And in the series 'The Dark Knight Returns', Robin was a girl after Jason died.
Wayne: Dude, relax. I only said I was excited for The Dark Knight.
Bruce: Sorry, I was nerding out for a minute there.
"Man, she's just so needy and clingy."
"Tom you gotta know she's not interested in you, you just fulfill her need to be liked and touched. She's needing out."
The act of analyzing data in great detail. When you spend hours working on excel or other stats programs trying to 1) figure out data and 2) analyze it. This often occurs while in college, fantasy football, and in careers that focus on research and analysis. On big problems, Data Nerding can go on for days.
Damn, I may never figure out what quarterback to draft for fantasy football. Looks like it's time to pull out excel and get to data nerding so I can decide on who to pick.