describe your baby's movements

for those of you who have felt definite baby movements already, how would you describe the sensations?

in the last few days I've felt what feels like a tiny whale tail slowly brushing against the inside of my abdomen (halfway between pubic bone and belly button), and yesterday I felt like a tiny foot was pressing against the left lower side of my belly for a full five seconds.

I'm a ftm at nearly 15 weeks so im not 100% sure yet if im not just having weird air bubbles moving around since my organs are getting pushed out of the way by my uterus.. but these sensations are super noticeable and I'm hoping they keep getting stronger!