kitten.
I was about 7 or 8 and our cat had delivered kittens.
There I was, laying on the floor of the TV room just watching Saturday morning cartoons. It was summer and my shirt was off of course (again, I was 7 or 8...so having my shirt off during the summer was a regular occurrence.) I was letting the kittens explore the room, crawling around as kittens do, and suddenly I felt a very sharp pain on my nipple. I sprang up to see that a kitten down there had just tried to breastfeed off of me.
So yeah...that was weird.