The action of hiding in a grass field because the police has just busted the party that has underage drinking involved or any other form of illegal activity.
Jack went grassing last night and almost got caught when the patrol car drove by.
When you drop a long-ass shit -- so long, that the tapered head sticks out of the water and then is reluctant to go all the way down right away when you flush.
Tom: Dick, look at the long-ass shit I just dropped. (Flush --)
Dick: It won't go all the way down -- it's gasping for breath.