Cupping is when the tread on your front tire begins to show a pattern of raised tread, sorta like it's trying to sprout horns all along the tread.
This is caused by overloading the rear of the bike, causing the front to "bounce" as you're riding along.
You can't really feel it, but it is noticeable when trying to lean into the corners.
The bike's balance point from front to back has moved back towards the heavy load in the rear.
Taking a short trip one time won't cause the cupping immediately, but you will notice it over time.
The first thing you'll notice is the different handling through the corners.
Incorrect tire pressure also plays a role when the back is not overloaded with "stuff."
An underinflated tire can also cause the same effect because the bike "bounces" along on the front tire.
The underinflation doesn't give the support it should.
An underinflated rear can also cause the same problem on the rear tire, and the lack of handling definitely more noticeable.
You can Google "motorcycle front tire cupping" to see images.