Fluid came out of nipple (not pregnant)

Kel • 3 January 2018👼💕 4 November 2019👼💕 29 February 2020 👼💕
Hello all. I've decided to post about this because I'm a bit scared that something may be wrong with me. SO and I were being intimate, and he was sucking on my boob. He was sucking pretty hard and he said some fluid came out. He said it was an extremely small amount, like a tenth of a drop. Should I be worried? What could it have been? I've been tempted to make an appointment with my Obgyn but don't want to look stupid if it's nothing to truely be concerned about. My nipple and breast look fine. No abnormal coloring, swelling, tenderness, ect. There's no visible signs of a problem. My self breast exam didn't feel abnormal at all. The breast in question feels a bit firmer in my grip than the other, but it's also larger than my other breast and I think that's why. Any ideas as to what it could have been? No fluid has come out since.
Forgot to add that I'm on Nuvaring, regular use (in for three weeks out for one).