Usually a porn jam will take place late at night so the participants may use volume when watching the pornographic videos without worrying that people will hear them.
Some great discussions on woman preference, porn preference, etc. will result of a porn jam thus increasing your friendship with your fellow participants.
Note: It has to be you and at least one other person, and there has to be at least one computer per person in order for it to be considered an official porn jam.
N-dizzle: Hell yeah dude lets have a porn jam!
C-ball: Yeah man just dont forget to bring your laptop we cant both just watch it on my computer.
N-dizzle: I know the rules foo I wont forget the laptop.
C-ball: Aight man porn jam tonight, at my place.