To me, if it's a naked male with an erection, then it's borderline. If he is in a sexually suggestive pose, then I might consider it pornographic (if he is in a suggestive pose nude, but not aroused, then it is not). If there is another figure there touching it or otherwise suggesting that something is about to happen, both nude, then it is porn. And if it actually depicts a sexual act...then I don't think I need to say it.

Hugging, kissing, or just being naked might be arousing to some, but that most definitely doesn't make it porn.

And then, some pornography can actually be artistic. Just because a good amount of it has little to no artistic merit doesn't mean it's all like that.