The best orgasm I ever had

We were just laying in bed naked, and as a goof I sort of wrapped my legs around her waist and laid on my back while she sat crossed legged. My balls were completely exposed to her and she just started touching my cock, playing with it, kind of absent mindedly. We're just chatting like normal, all the while I start getting hard. I'm trying to not to react as she starts massaging my balls. I don't know if she's doing this on purpose or she's just reacting to my throbbing and growing. She hasn't actually started jerking me off, just used her fingertips to tease the bottom of my penis. Then she starts using the base of her hand to stimulate my cock, rubbing it along the bottom, like she's kneading dough. Again, I don't know if she's planned this, but she has to feel how hard I'm getting; my breathing is starting to get heavier in spite of trying to keep it cool. It's too much though, it feels so good. I involuntarily moan in pleasure, and that's when she finally grabs my cock and starts jerking me off in earnest. It only takes about a minute, but I fucking shoot a load 2 feet in the air. She's shocked. I'm shocked. I didn't even know I had that in me. Rope after rope ejaculates all over my chest as my girlfriend watches in amazed silence, her face in a wide smile. She starts picking it up and playing with it. I can't even move for at least 10 minutes from the delirium. I've been chasing that orgasm ever since...