Well he is a bit old to be just "trying out" discipline on him, seems like you should have had that figured out when he began needing discipline which is at one year of age. Discipline does not mean punishment, it means teaching. So think about it, how do you learn things? How did you learn not to touch the skillet while you were cooking? i bet your mom told you not to.. but i also bet that once or twice you were careless enough to get burned anyways, but after you felt the pain you remember it and are much more careful than if your mom just told you not to touch it. We learn things by finding out what happens when we do things. if we don't like what happens, we tend to not do that anymore. If we like what happens we do it again. If we do something and we get the result we want sometimes and other times we don't, we will try to be tricky and try it again in a manner that will get us what we want. If we become convinced right off the bat that we won't succeed at all, we won't try it again.The discipline must fit the development stage and must be appropriate to teach cause and affect, but since its YOU making the effect, you can control it so it does no actual harm to the child, and prevents the child from serious harm later.

Take a look at this article and see if you can get some inspiration on how to handle things:
http://pre-kteachingtools.com/article2/?cat=6