P.K.
Distraction is what we try to use. Take the word "no" out of the situation if possible. And, try to distract yourself, too, from laughing because that is reinforcing his actions. I know that's sooooo hard to do, though. As far as distraction for your son, for example, my son doesn't want to wear a bib, so I've found that if I give him a choice of colors he's so involved in the choosing that he forgets he doesn't want to wear the bib. And, it's probably not that he doesn't want to wear the bib, but that he doesn't want to be told what to do, period. And, believe me I know about the diaper changing because my son has some sensory issues which include gravitational insecurity (e.g. hated swinging) so putting him on his back was a nightmare. It's much better now, but of course he still doesn't want to have his diaper changed, so I've found distraction works there, too. I know some people use mirrors beside changing tables for infants, but we're past that point. My son happens to like the flavored lip balm we've used on him, so I let him apply it himself while I change his diaper. (Under our observation, of course, as it's a choking hazard.) For what it's worth, most moms I know say their children grew out of the difficult diaper changing phase much earlier than my son, so hang in there.
As far as not letting someone kiss him. I feel strongly that no child should be forced to let anyone kiss them at any time, even their own parents. That does not mean I condone the child hitting, but I think that addressing the hitting or pushing, as you put it, should be addressed, but that no kiss should be required as "punishment." (Not that you said you did require one.) It seems to create a negative association with affection and punishment. And, implicitly tells a child that he has no say in who may touch him. Of course, I do not think that saying, "Give Grandma a hug goodbye" should never be said. I just believe that if the child refuses that his choice should be respected. But, again, I DO think the pushing away in aggression in the context of a person with whom he is normally affectionate should be addressed.
The dog... We are currently looking for a new home for my cat of 13 years. I think the situation with an animal depends on several factors, including the age and nature of the animal and the resources of your home. We live in a townhouse and do not have a garage, yard, nor interior layout that would allow our cat to roam about in a large area while remaining apart from our son for significant periods of time each day. Our son has never been aggressive with our cat, and our cat has never been aggressive with anyone before. However, when a small child gets in the face of an animal, even if they are being affectionate, it can feel aggressive to an animal, and that animal can react on instinct. Our neighbors' grandson was simply hugging their cat when the cat bit him on the head. They had to take him to the hospital. Our son while crawling would sometimes back our cat into a corner. Well, of course the cat scratched him. Now that our son is walking I can not possibly be alert to similar situations all day. Unless we put the cat in the guest room they are on top of each other all day long. A disaster waiting to happen. We feel it is unfair to both our son and our cat to keep them together. Clearly, people have animals with children, so there may be a solution for you. Can you separate them for those times of the day when your son is most likely to become aggressive? That might allow you to foster a good relationship between the two during the good times of the day, while preventing the negative associations from forming during the cranky times of the day. And, prevent any possibly accidents.
I'm curious about the information another poster provided from the child psychologist Penelope Leach. This paragraph in particular:
Some experts suggest that parents offer an angry child a harmless way to "vent" his pent-up fury, such as pummeling a special pillow. This, in my opinion, is a mistake. Anger is a feeling, and feelings don't get "used up." In fact, it's clear from recent research that "harmless violence" is a contradiction in terms. A child who's encouraged to wallop his pillow in anger is more — not less — likely to see walloping a person as an acceptable alternative.
Don't adults "use up" their anger when they exercise or engage in sports like tennis which involves (gasp) hitting something? And, when I write that I'm curious I do mean it literally because I'm not sure what I think about that idea. Isn't it possible to teach a child that a pillow, an inanimate object, is where they take out their anger and not on a person? Now, if the pillow is one of those that is made to look like a face, that's a bad idea. And, sometimes venting, even verbally, can just arouse a person more, so I don't know. Anyone have an opinion on this topic? I'm going to research this one and get back to you if I find anything compelling.
Good luck!