A Timelord Discount is not as cool as it sounds. Basically it happens when a customer asks for items at sale price a week, month, or year after the sale is over. The justification is usually something along the lines of "the item wasn't in stock when the sale was going on, and it's only fair that you should honor the sale price on these fifty hats I want to order now." In other words, if a baseball cap is on sale for $16.99 five months ago, and the customer was not able to order the white color five months ago due to inventory issues, they feel entitled to request that you honor the sale price on the white ones now, when now the hats are $35 apiece. And they want a dozen of them. When this happens to an item that is discontinued, it turns into a Dodo_Discount.
Another variation is when they just placed an order, it shipped out, and they still want to apply a coupon to their order, or if they want the deep discount applied to a smaller purchase that followed the purchase they made without the coupon.