Ray Leonard did it to Davey Green. Watch, carefully, the 2nd knockdown in the DeLaHoya/Ruelas fight. Check the replay, around 11:13, then at 11:19 in and you'll see Oscar punch the Ruelas left out of the way of the DLH right. http://www.youtube.com/watch?v=K8dGyHltDzk Also, it is a good move inside. Push/punch/pull his right glove out of the way with your left to open a way for your right.
parrying is blocking with your palm,..pulling your opponents guard down is called drawing, you can use drawing in the pros but not in ametuers.