I'm not an Uncle. I'm an only child. But a lot of my cousins have kids. Like a shit ton of kids. And I'm American too
Our big extended family is just pretty casual with partial nudity though. Especially with me since I'm in my underwear or just in work-out shorts most of the time. I am the "creepy" one in the family though.
Plus, I've fondled a few of the younger tikes. Hence why I said "when we are together in private" I don't get erections in front of regular family. Just the kids since I know they dont really think anything of it but it still gets me rock hard knowing I'm fully erect in front of a little girl's face. One time I babysat (years ago) and she was watching Dora. I took my cock out and started stroking. Came all over myself as she was watching tv just a foot or two in front of me.
I then told her to go to the bathroom and get me a towel. She quickly ran to the bathroom and then handed me a towel. She said, "What happened [name]??"
I told her, "I just dropped something sweetie. Go watch Dora, okay?"
She said, "Mmmm-hmmmm. Okay!"
Then she looked at my cummy cock for a split second, did a double-take, then jumped onto the floor and started watching Dora again. Was pretty cute but I don't think she realized anthing