For example, "Apple schmapple" to mean "I scoff at your Apple product".
As you'll see on the linked wiki, usage tends to be a bit more specific than general mockery.
For instance, I would take "Apple schmapple" to be calling into question the "rightness" of even calling the product an Apple product.
In essence, you might be understood as saying "You call that an Apple?" which could actually imply respect for the company's (usual) offerings.
That said, I'm sure the listener could determine from context how loosely you may or may not be using this construction and what opinion was being expressed.
You may also be interested in ablaut reduplication, which involves changing medial vowel sounds to create a sing-song effect. ("Sing-song" also happens to be an example of this construction.)