What is it?

Si
I was having sex with my SO and he felt an odd squishy ball that wasn't firm but it was at the same time. It bounced. Is that ok? I called and asked my dr what it was. He and i thought it could be my g spot. Then my dr said it was my uterus. I don't know what it was. Well... what was it? I don't understand is that ok or normal?