I just wanted to get something off my chest that's been bothering me. I imagine a lot of the suggestions or thoughts for what I'm experiencing will be similar to this recent thread, but still want to share.

I sometimes get an erection when playing with my nieces and nephews, especially when they are playing on my lap. This is extremely uncomfortable for me as you can imagine, but also scary: it makes me feel like a latent child abuser.  I tell myself my reality doesn't correspond to such a low level - I am almost 10 months clean from masturbation and several years clean from pornography, and I have never abused a child. At the same time, the arousal is very real and so are the insane follow up thoughts, and I am honestly worried there is something wrong with me.

I also tell myself is that having an erection is just a natural response to an intense feeling of love, whether that be for a woman I'm dating or a cute niece or nephew, but even as I write this now and I'm kind of disgusted by this rationalization, and having a hard time honestly assessing if there is any truth to it.

Anyone else ever experience this or have thoughts on the matter?

…or it could just be your body’s natural response to the physical sensation of someone squirming in your lap. People get it from sitting in a car on a bumpy ride. It doesn’t have to have any deeper meaning. Just reposition and move on. 

Your obsession with abuse proves that you are very far from that. If you would be ready to do that, you wouldn't be obsessed with that. People are only obsessed with things that they see as bad. Research shows that those who are obsessed that they will do so and so, are actually the most far from doing it. 

You are %100 Normal and thoughts Do NOT! mean you are abusive!. You can look up some research on pocd (Pedophile OCD) for help/info.
Most normal people have such thoughts and just move on. You are normal in your thoughts, just abnormal in your reaction to your thoughts.
There's no reason to freak out, as your thoughts will not cause any harm. The ironic thing is with scary thoughts is, that the more we freak out about the fact that we are having such thoughts, the more intrusive those thoughts become, which farther convinces us that we are for sure crazy. Which then causes us to start thinking those thoughts more and more often. And it makes us feel like we are FORSURE crazy. 
Here's a tip from me as I struggle with this too, accept your thoughts as they are and feel free not trying to force those thoughts away. The less upset and more excepting of your thoughts and yourself, the less intrusive the thoughts will be.  Remember, Its actions we do or dont do that make us abusive or not, not thoughts.
Good luck, Feel free to ask for more info.