Fingering My Belly Button

My belly button is really sensitive, and very stretchy. My entire belly is very elastic! This lingerie lets just my belly button show a little bit, but the bottom quickly unsnaps for easy access. One finger slides into my belly button, but it's surprising how many fingers I can actually fit into my tiny hole. The stretch marks surrounding my belly button allow my skin to stretch so far that I can nearly slide all my fingers inside. I can even stretch my belly just a bit farther to slide in even deeper still. It's so sensitive and red already, but my belly button can handle more vigorous play still. I tease it and show off my innie belly button. My tiny waist is slim, but expands to surprising lengths! Should I push my belly to inflate even more, or should I try to slide one more finger inside my belly button?