Yep, I'm quite the silly one on the regular because I enjoy being expressive, no matter which emotion I'm feeling. Silliness just happens to be one of my favorite means of expression, but it wasn't always that way. As a child, I so dearly wanted to express myself and be liked, but I was always so shy and terrified of others' judgment (you know how kids are, they judge you if they see weakness), so, I just balled up and hid away instead, certain that self-expression and silliness were more trouble than they were worth.
Yet, a few Pe-doms would eventually show up in my life, so it was inevitable that I would feel accepted by them without judgment and finally join in on their antics. I had an ESFP friend in particular during my Freshman year of high school who was the embodiment of letting lose and unleashing total, silly chaos. If something was fluffy, she'd touch it, or if we were walking by the accessories section in a store, she'd just have to try on some hats, and she encouraged me to interact more with my environment, too. She even gave me a nickname by randomly yelling out the first letter of my name. She really brought it out of me and made me a whole lot less shy, and I think that furthered my need to express myself, and I became more comfortable with my Ne and letting harmless things like silliness slip through the filter, and eventually, it would feel natural.
Nowadays, my silliness is still reserved for casual situations (rarely ever professional settings or first impressions), but as soon as I can establish myself as a sincere hard worker, my silliness (usually by means of modulating my voice), will come out with most anyone who I feel will be receptive to it.
As for my brand of silliness, I typically like to be contrary or ironic in an inoffensive way, like: "If you ask me, I think we would sell more units if we set this toothpaste display near the onions in produce."
And with friends I know more intimately, I also enjoy total surrealism or nonsense regarding interconnecting ideas, even glottal sounds. My ENFP friend started mimicking the sound of a creaking door by inhaling air through the side of her mouth one day, so now whenever she does it, I roleplay that I am a fly catcher determined to "finally ketch that pesky boy fly". xD
