skulkbooking

The act of browsing Facebook from someone else's account, typically a spouse, family member, or good friend. An activity commonly undertaken by one who does not maintain his/her own Facebook account.

Dude, how'd you know I was in N'awlins?

I saw on my girlfriend's Facebook page that you posted a picture of that "Huge Ass Beers" sign from Bourbon Street.

Shit, dawg, that's some shameless skulkbooking!