1. the feeling or action resulting from experiencing a particularly exciting event within the canon of a certain fandom, especially an event that has been anticipated for a long period of time, has a particular amount of tension building up to it.
2. Any extreme outburst of energy related to one's obsession with a fandom or an aspect of the fandom, especially when seen in random unrelated situations.
3. to experience a fangasm.
"The Prisoner of Azkaban movie was a fangasm for Sirius x Remus fans."
"If Kishimoto reveals that Yondaime is Naruto's father, I'm gonna fangasm!"