A Strange Coincidence, or, What's a Dikfore?

I've seen the Dikfore t-shirts, but I fully admit I didn't get the joke. I remember noticing them around the time people started wearing Darfur t-shirts. I assumed there was a connection, as they were both plain and simple, with the single word written in reasonable height across the chest. I thought perhaps the Dikfore people were pro-genocide, or were just trying to get a rise out of the Darfur people.

I googled Dikfore just the other night and got the joke.

The very next day, I was flipping through the channels (of my amazing new cable television service!) and landed on a shot of Chevy Chase and Dan Aykroyd in military/hunting attire, standing in the woods having this conversation (as remembered):

Dan: Do you hear the Dikfores?
Chevy: What's a Dikfore?
Dan: It's what you pee with.

What are the chances that the day following finally being let in on the joke, I would discover the apparent origins of it?!?! I can't figure out the movie, but per IMDb.com Dan and Chevy have been in surprisingly few movies together. One of which was Caddyshack II, which I choose to believe was the movie that, decades later, spawned 1000 t-shirts (it spawned little else, so it may as well get credit for this).

If you know whether or not this is correct, please let me know.

I love life's little coincidences!