I don't actually get into buddy testing in the purest sense of the word where I write code and have someone else check it and vice versa. But I use the same concept. I write test scripts, then have a buddy check them out. Independent V&V. Basically, buddy checks are peer reviews where you have someone independent check your deliverables for errors. They will catch a lot of things that you don't, because they are not reading into the product what you thought you put there. They are reading what you actually put there.
Make sense? Having someone else proofread your document before you send it is a form of buddy testing.
I actually think of buddy testing (or paired testing ) a little differently.
I use the terms to mean two Test Engineers sitting together at one terminal - only one typing for a given stretch, but both collaborating out loud on the test strategy. It is a great way to train (and gauge the learning of) a new tester...but it is also often a productive way to test any feature. When what and how to test is not obvious, two heads working in concert can be better than one (or than 2 testers testing concurrently at different boxes and with minimal communication).