To look at someone through a mirror. Preferrably that person be showering. This refers to the famous substitute teacher/little league baseball coach, Doc Fuss. Doc Fuss was famous for watching young kids shower after gym class by looking at the children through mirrors.
Bob: You're mom gay
Steve: Your dad lesbian
Bob: Your granny tranny
Steve: Your grandpap a trap Bob: Your brother a mother
Steve: Your niece obese
Bob: Your family tree LGBT
Steve: Don't make me do it.
Bob: Do it!
Steve: Your cousin be fussin
(Bob then explodes, barely leaving Steve alive)
Fusking is simply using a program to extract files names from a website that would seem obvious. Like 1.jpg, 2.jpg, etc.
For the record: These other definitions aren't "fusking" wrong, they're fucking wrong. If you're typing "s" where your "c" is... consider a keyboarding class, n00b.
Amber: Oh hey Nikki, what are you gonna do tonight?
Nikki: I'm gonna try fusking in our friend's private photobucket for pictures they wouldn't want us to see.
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.