I got into pro-am porn through (I've been swinging since I was 19). First for for a lady who had a pay website. I'd swung with her and her husband, and they asked if I wanted to do video for the site. We'd do a scene whenever I came to their town (Pittsburgh). It was cool, but the pay was almost nothing.
Later, I did vids for a couple who owned a small production studio in Allentown. They had seen me at an orgy, and were impressed with my size, and my ablity to stay hard after shooting my load. They paid better, and had a lot of different female performers. I told them I was only into females, but would do any females they had. This got me more work -- I did BBWs, etc.
It was great, getting paid to fuck! The only hassle was having to save my cum for the cameras. I normally masturbate in the morning, but that was a no-no if I was doing a vid that day.