A while back I was browsing through some porn online and I came across one that said the guy cums twice. I figured it would just be chopped up and showed him having a couple of different orgasms, but I watched it anyway. I'm glad I did, because he was having sex with the woman doggy style, and about halfway through it he stopped and pulled out, shooting his cum without letting go of the girl. Then, without missing a beat, he slid back inside her and started pumping again, never getting soft. I couldn't believe what he could do, and I was horny as ever watching him, cumming before it was over. When he was done she spun around and he stroked himself off to his second orgasm on her face.
Since I watched it the first time, I tried many times to copy what he did. I would watch it and try to cum quickly and start again, but every time after my first orgasm I would lose interest and get soft. One night however, I was determined to do it. I hadn't cum in 3-4 days so I was primed and ready to go. I stripped naked and turned off the light, brought up the video and started playing with myself, getting hard almost immediately. I paced myself for a while, and when he came the first time I stroked hard and fast, blowing a huge load on the carpet. Like always I started to get soft, but I focused on the fucking in front of me and kept stroking. This time, I started getting hard again, and after a couple of minutes I had another full, hot erection. I wasn't feeling much at first, but after about 10 minutes or so I started feeling some pressure I hadn't felt before. It was almost on the verge of hurting, but it actually felt really good. Another couple of minutes went by and it felt like an orgasm was coming, but it wasn't building like normal. I kept stroking as hard and fast as I could, and all of a sudden it broke free and I knew I was there, and a few strokes later I was cumming for the second time. It was amazing. I had never felt an orgasm like it before, my penis was throbbing and tingling and I felt warm all over. I couldn't even touch it, I just sat there in a daze, my hand covered in cum and a few white lines between my feet.
It was definitely hard and I haven't tried to do it again, but the one time I was able to it was absolutely worth the work.