Your child's behaviour seems to be an attention-getting device. Instead of punishing him, use behaviour modification techniques.
First of all, try to ignore the undesirable behaviour. Instead give attention only to desirable actions. The child will quickly learn that some behaviour is not noticed and therefore useless.
Make a behaviour chart with him, where small lists of desirable and undesirable behaviour are clearly written. For every episode of breast touching etc., he gets a negative mark, while for every desirable behaviour he gets a red star. Red stars can be exchanged with a small gift at the end of the week.
Avoid labelling him as bad or dirty. Highlight his positive traits to encourage him. Hopefully you will soon see a change in him.