Would it be possible to do this...?

Hi, I'm a bit stuck in Excel right now, not sure what to do next. A co-worker of mine made a spreadsheet for listing new valves as they come into inventory. He made drop down lists in each category for describing each valve (Type, Size, Brand, and Quantity)
with each drop down containing every description available (such as 1" or 2" for size, Gate or Butterfly for Type, etc). What he would like to do is speed up the data entry process, so that every time a description is selected from a drop down list, it will be copied below it on the spreadsheet, and the next time to the cell below that, and so on. He asked me if I could figure out how to do this, and I thought perhaps a macro could be created, however my VB is very rusty, and I was wondering if, and how this could be done? Any help would be greatly appreciated!