2 1/2 Year Old Exploring His Body!!

I would calmly and consistently tell him that we have to keep it in our pants except when in the bathroom and tell him to take his hands out of his pants every time you see him do it. But remain calm and stay cool - it's so normal and every little boy "discovers" himself. Divert his attention and give him something to hold in both hands in public. :) Pick your battles - start with telling him that this behavior is a "no no" in public and then add in your home. Explain his pee pee is private and not to show to anyone else except Mommy. Just don't show any emotional stuff about it so he doesn't get extra attention by doing it. Sigh, isn't being a Mommy fun? :)

I agree w/ the mom's below let him know that is something you don't do in front of others. I also suggest getting a book called "From Diapers to Dating" it really helped me with some issues and questions that I had.

Don't harp on it, because then he'll start doing it for attention. But do let him know that it is not acceptable behavior. It's probably a phase and he'll grow out of it.

Explain to him that the parts of his body that are covered when in a bathing suit are HIS private parts. Explain that only he, his mom, dad and the doc should touch those private parts.
Also explain that while he may touch them as much as he likes, it is something he should do in private, like in his room. Don't yell, embarass or humiliate him about this. It's normal.