Often abbreviated and betterly known as TD, the most famous of the 'D family.
This is when you feel a need maybe after eating, or may need to in the near future, you would take a 'tactical dump' to avoid having to dump later when there may not be a toilet or even be put in an awkward place or position, if used properly this would rule out 'power dumping' but as the rules of 'dumping' have yet be perfected this is not the case.
Mum to son:- We'v got a long journey ahead take a Tactical Dump before we leave ther may not be a toilet stop before we arrive
Football manager to players :- take a TD before the game, dont want any of you shitting yourselves on the pitch
Im about to go clubbing better TD before i leave so i dont have to sit down in the grimey toilets in there.