When/how did you experience your first real orgasm?

Whenever I first started masturbating and having sex, I thought I was having orgasms until the day I finally actually had one at the age of 16. I was watching porn and dry humping the arm of my couch...then it was like this overwhelming feeling came over me and took my breath away. It felt like a warm explosion radiating inside of me. I'll never forget how incredible it felt that very first time!!