Awkward Sexual Experience in Reboot day 95

After the first 90 days of no PMO and no sex, I have decided to go for sex if I get chance. Somehow one girl I have known for a while wanted to meet me yesterday. I said yes and we met. I knew she was kinda attracted to me in the past but I dont really feel anythig special to her. Anyway one thing followed another and we found ourselves in her apartment. Some making out and I was very healthily hard. I performed some oral sex and then she took the turn. The strange thing started, when she started to perform, I started to get soft. I was like Wtf? I must say she had a good techique too. Then after 2-3 mins I became semi-hard and ejaculated. It was not a orgasmic experience, it was just like my body putting out the extra stuff! I was kinda surprised about wtf has just happened, luckily she didnt make a big deal out of it. We didnt go for the second round coz she was going a b.day party but it was very strange. Anybody had a smilar experience? Because, seriously I was expecting a goddamn explosive orgasm after 95 days of abstence. Ideas? Experiences? Enlight me please...