To slack off with many people at the same time.
I'm not done with that yet; I've been multislacking.
To be slack in several ways, against several people, more several reasons.
Public schools are so multislack.
Doing multiple slacker-esque things concurrently.
I'm the king of multislacking. I spend hours a day surfing the 'net, watching random TV shows, and eating week-old pizza.
A person who is a muti talent at doing nothing of human interest but only in human suffering.
Friend: Hey dude you ever get that job scrubbing those waste cans at the abortion clinic?
Dude: No man, I couldn't find any straws.
Friend: I may be wrong but you might be the worlds best multislacker!
To engage in two or more unproductive activities at once.
"What are you doing?"
"Playing World of Warcraft, watching Judge Judy, and talking on the phone."
"When, quit multislacking and take our the garbage."
Doing two useless things at once.
"Dude, I can't mop the living room because I'm multislacking a documentary about Beany Babies while I'm planting celery in Farmville."
Having two or more non-work related web pages, open on your work computer, at one time.
I was at my desk, multislacking, when my boss walked in and I had to close five browsers in .5 seconds!