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 only reason 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.
To do a particularly nerdy activity such as playing a videogame, writing computer script, or doing math problems, and zoning out while doing them.
Oh, sorry i was nerding out there.
Try not to nerd out this time, ok?
Oh fingernailpiss, he's nerding out again.
you know you are nerding out when:
bowties, newly printed warm theses, and talks on evolution and human variation make you wet in the panties.
the majority of your boners are facilitated by the library, in one way or another.
you spend every friday night and the wee hours of saturday morning at PANCAKE 24 HOURS.
You only get ten academic boners in a lifetime. Ashley just got one. She must be nerding out.