Something not needed. An extra. Pointless. If something is already there and something is added very similar. A carbon copy.
Having a fridge in your room is a wool cap because you already have one in your kitchen.
4👍 4👎
The residual left at the tip of the penis after a male ejaculates into a napkin or a few squares of toilet paper, most likely after masturbating.
After going on a 3 day long, masturbatory binge, and ejaculating into every napkin he could find, Jim had a big enough White Wool Cap to fully clothe a tiny, Chinese village.