fly dump 

Using a public restroom to defacate and then purposely not flushing.

I went to use the washroom but someone did a fly dump before I got there.

fly dump by The Last Victim January 14, 2009

fly dumping 

The act of throwing your garbage in someone else's trash to hide where the gargage came from.

After an underage drinking party, you go fly dumping to get rid of the beer bottles and other contraband in an apartment building dumpster or toss the garbage in a neighborhood lawn.

fly dumping by Greenpiece January 30, 2007