I've been with 6 cops. They were all very hot experiences, but none of them were open to being a bottom, so totally different experience there. One of the hottest experiences I had was with this cop who hit on me in a college restroom. He was very aggressive and forced me (didn't take much forcing), to have sex with him right there. Then he started coming over to my house on a regular basis. After several months, a friend of mine told me about guys getting busted in that same restroom. I figured he would know about it since that was his beat. He gave me an evil smile and that's when I knew he was the one arresting people.
It really turned me off knowing he was arresting guys for doing the same thing he had done with me, so I backed off. Then he started getting demanding that I see him again. He told me he had secretly filmed us during our first encounter, I guess as some kind of veiled blackmail to get me to see him again. He told me he had lots of videos of him having sex with other guys which freaked me out even more. After that it turned into an all out stalking situation. He never directly threatened me, but it was apparent to me he was giving me subtle cues that something bad could happen to me if I didn't do what he wanted. Luckily, I moved to the other side of town shortly afterwards which made avoiding him much easier.
Be very careful with cops. They have a lot of power and it can be tempting for them to abuse that power to get their way.