When two or more people with the Harry Potter Syndrome have a form of 'battle' either in person, on fb, or over texting, in which they pretend they are one of the characters from the Harry Potter series. They use references from the books, recite spells and cantations, and try to make it as epic as possible. It is all verbal, unless of course if it is in person, in which case they must use the proper wand movements when jinxing or spell casting. A story-line can go along with this, made from the duelers' imaginations. It occurs spontaneouly and inner purpose of it is to show off your knowledge of everything Harry Potter and the aftermath of it is that one or all of the involved duelers will deny ever being involved in such an activity.
Dueler 1: EXPELLIARMUS!!!!
Dueler 2: *ducks behind witch sculpture* BLIMEY! Can't you just accept that Hermione loves me?
Dueler 1: NEVER! You filthy ginge, she's mine! *hears a crack as Hermione apparates*
Hermione: I DONT LOVE EITHER OF YOU!
Dueler 2: Oh yah? AVADA KEDAVRA!
Hermione: *falls to floor dead*
Dueler 1: What a shame... wanna go get some Butterbeers?
Dueler 1: We had a Harry Potter Nerd-off last night!
Friend: Oh really?? *snickers
Dueler 2: Nooo... I dont know what you're talking about!