Yea, but usually you slack in one area...Like slacking in school, slackin at work, slackin on the field, slackin in the sack..haha
So, you do slack ON something....unless, youre so much of a slacker, everything you do is slacking....but then you still slack ON life, or then it would be slack IN life....
I'm definitely slacking on school work. I've only got a 20ish page term paper due and an Excel project worth a third of the total points in the class due in a couple weeks
Also, we just got a crap ton of snow and I have yet to raise my car back up.