It is common that no-one can actually understand the nerding, not as a result of the complexity of information presented but as a result of the nerds proximity of his/her head to his/her upper, upper colon while speaking.
When this happens someone is said to have 'nerded'.
'Nerding' is a sin commonly commited by students of the computer sciences, of physics, and other area of science, but is also regularly observed in those studying humanities, the arts or nothing at all, who have extracurricular interests such as world of warcraft, comic books, sci-fi or the manufacture of 16th century table legs in northern france.
This is how you can tell someone has had their moment of nerding brought to a needed end, and is your cue to regain consciousness and begin paying attention to what is being said. At this point the conversational theme has decayed to a barrage of deserved abuse directed at the nerd.
I dare not give a direct example of 'nerding' as it may cause you to loose the will to live. If you really need one just ask a nerd how to adjust your IP settings.
I will also point out that it is possible to nerd without knowing if the people you are with are too polite, or just want to bitch about you later. Just look for the tell tale signs that include rolling of the eyes, sideways glances, involuntary actions of fatigue and snoring and in extreme case soiling of one self as to find an excuse to leave.
But these are not always present.
Hell, I may have just nerded all over you.