Photographing Work Colleague Naked?

I have a good relationship with a male work colleague, who is a bit older than myself. He's in good shape and knows that I enjoy photography as a hobby.

Our conversations sometimes borderline on flirtacious. We're both in relationships.

He's joked that he'd pose naked for me. Of course I laughed it off but the more I think about it, the more I want it to happen. I've masturbated thinking about it more often than I ever thought I would. I want to watch him undress in front of me and to set eyes on his naked body. My bulge watching results suggests he would have an ample cock..... I encourage him in my fantasy to get aroused in front of me.

I can't express how much I want this to happen. Should I pursue it? Of course I'm worried it would turn into something more but at the same time it would surely be pure lust. In my fantasies I suck him off, nothing more than that.

Maybe I'll post back if this does happen.