A person who supports more than one, or many, fan groups. This person does not need to be in one specific fandom or a fandom at all and is not required to keep up with that group at all times. This person simply supports or approves of the group itself, and/or their work.
Similar to multi-tasking with computers, it involves engaging in a variety of applications on a computer. However, in multi-slacking, this definition is restricted to include one or more of the following: gaming, chatting, listening to music, web browsing (non-educational), hacking, pirating, posting on forums, watching videos, or viewing pr0n.
AP Comp Sci is the perfect chance to practice my multi-slacking skills.
Engaging in many small activities at once, none of which are productive. Usually, but not always, involving a computer and its applications (iTunes, AIM, YouTube, etc.), can also include watching a movie or TV show, listening to the radio, talking or texting on the phone, or any other ultimately trivial, meaningless activity.
That dude was multi-slacking like mad when he should have been working.
A person who can slack off on multiple things at once. Not to be confused with a multi-tasking slacker.
Multi-tasking Slacker: I'm watching T.V., playing an MMORPG, eating cheetos, and talking to my friends on the phone instead of doing my English assignment.
Multi-Slacker: I have an English assignment due tomorrow that I haven't started, my laundry's piling up in the bathroom, and the electric company is threatening to cut the power because I haven't mailed the bill for last month.