That's where you take a dump in a box, wrap it and put it under the tree. The best way to accomplish this to attend a Christmas party, bring a real gift and let every body know that it is yours so they will associate you with that gift. Then slip the Brown Santa under the tree without anybody watching.
This can be done at any party or celebration such as a birthday party or wedding, and with any inappropriate gift: vibrators, gay porn, roadkill and cremated remains.
You should have see the boss' face when he opened a Brown Santa.