When Is Nudity Inappropriate?

I've always been pretty comfortable with nudity.  I was that kid who would strip off her clothes and go running down the street anytime supervision eased up just a little.  My brother and sister surely chased down my naked butt at least 100 times.  And that's just when I was a toddler! 

I regularly walked around the house wearing only underpants until I was nearly nine.  I began frequenting nude beaches in my late-teens.  I've never been to a Jimmy Buffett concert where I haven't flashed my boobs.  I think nothing of hopping into a hot tub with friends wearing only my birthday suit and a smile.  And then there were those pictures. . .I guess I'm saying that I'm okay with being naked and with other people seeing me sans clothing.

Naturally, my son has seen me naked plenty of times throughout his life.  I mean, he nom nomed on my milkalicious boobs until he was almost 13-months old and he's bathed or showered with me plenty of times.  He often sits on my bed and watches me while I dress in the morning and he usually sees me disrobing as I get ready to jump in the shower each night.

My son will be three-years old in a few months and I'm wondering if I should begin to exhibit a little more modesty around him.  He understandably used to light up and smack his lips when he saw my exposed breasts.  I get that and it makes sense.  Now he is very curious about my pubic area and I'm not sure what to make of that.  He's asked why I don't have a wiener, which I think is kind of funny, but he also runs up to pat my pubic hair anytime I don't slip on underpants fast enough, which I do not find very humorous. 

I know that he isn't looking at me in an inappropriate way or sneaking touches to be sexual, but I don't know when or if his natural curiosity should be curbed.  I do wear all of my clothes when he's around so he probably thinks it's funny or interesting that I look different than him when undressed.  I absolutely do not want him to develop any weird feelings about the human body and I want him to feel comfortable in his own skin.  But I also don't want to raise Oedipus. 

Are you a parent of a boy?  How old are they now?  Did they see you naked in their early years?  When did you stop letting them see you naked?  Are they funny about nudity, their own or anyone else?  Do you have any suggestions, thoughts, or advice?