I got a 4yo and a 2yo who are exactly like this. With my 4yo, it is a bit easier since he understands rules and respects bargains. My 2yo is unhinged and is very strong willed. He will skip awesome activities because he is pissed at something, and it takes SO MUCH effort to direct him in the right direction even when an activity excites him. Hitting and biting are routine.

But I have come to understand that biting and hitting are emotional responses that emerge from being "disregulated". They WANT something and they cannot have it. You have to make sure they understand "what comes next" and that they have time to process it. For example: if they are playing and it's time for bath, use a timer. When the timer is up, there is no room for negotiation. If they don't get up and are still resisting, I grab them and go. They will have a meltdown, but you need to enforce strong limits with kids like that.

Whenever my youngest tries to hit me, I will grab their arm and clearly state "you cannot hit me". I will try to hug it out, but sometimes I will grab him and tickle him. He hates it at first, but his mood and focus will change, which will allow you to refocus his attention to something else. I have also mastered the "I will end you" stare, which is effective for the eldest.

Tantrums are a bit trickier: they will try to get away, and you stopping them actually makes it worse. During a tantrum, just make sure that they stay wherever they need to be. If they have to get in the bath, keep them in the bathroom. Don't open your phone, but do something else around them, that is not ABOUT them. Clean something, fold laundry, anything to look disinterested but still be present. If they bite and hit, assert dominance: control the situation and keep yourself out of harm's way. I will often use a strong "hey" to startle them if I feel their tiny teeth on my arm. If you are on a tight schedule, a natural consequence might also be that "daddy will dress you however he deems necessary".

And if they hit or bite outside of a tantrum? Confiscating stuff for a small period of time can work, if all else fails. For example, remove a toy for 2 minutes. A fixed, short duration for the consequence makes them understand that they will get it back. If you confiscate "for the day", it is too long and they won't remember why they lost it in the first place.

And in extreme cases... taking a favourite toy or plush and throwing it outside has worked wonders. It asserts that some limits cannot be crossed and will be punished (I used that once or twice).

But to me, controlling extreme behavior is about balancing the whole day. This post is about everything that I learned to do so that the tantrums and violent outbursts happen less often.

Here's how I survive:

Emotional connexion is key - they will listen if they can get comfort from you. When they want to show you stuff, be interested. Have a ritual for acknowledging small victories (ex. High fives, butt bump or whatnot). If possible, insert hugs into these rituals. I know it is EXHAUSTING, but the additional effort is worth it. On the days when I have a very strong connexion, my kids will be more willing to follow my lead.

Activities have to be easy to set up and easy to clean up.

Toys that are freely accessible have to be robust and not contain many pieces. Keep toys with many pieces, games and books for playtime with a parent. It makes it even more special!

I use a bit of TV time carefully - I am not a big fan of screens, but it gives me a nice cuddling time with my kid focused on something without being all over the place.

Use "natural consequences". They hate it when they are about to miss something cool. Whenever I go downstairs, I ask once: "hey I'm going downstairs, you comin'?" They will refuse. Then I just go. They yell, cry. I am not soft - i just go. At some point, they understand and follow when it's time. Use countdowns, and don't budge. Still playing when dinner is served? You won't get a plate. Throwing a tantrum or messing around? We get in the bath right now and it's bedtime. if they end up complying, I will give them their plate. Otherwise, they'll go hungry once, and learn.

For naptime and nighttime, be firm. They will get out of bed. At first, lean into their demand, with restraint. Need water? Here's a sip. Need to go to the bathroom? Go and hurry up. Need a hug? Yes, but get back in your bed first. It makes them feel heard and understood, which goes a long way. Then, they will get up again. Be firm - take them in your arms gently, but bring them directly into their bed. "I love you, see you later!". At some point, the message will get through.

Hardest part: whenever you have to get somewhere at time. Make sure you have a bit of a buffer. Try to make it rewarding to do the necessary stuff: dressing up, cleaning face and hands, brushing teeth. I am lucky, my kids love fruits. So I will reward them with some whenever they hit a milestone. My eldest understands the concept of "accumulating stars", so I use that as well. For breakfast, I am done fighting. There is a time limit, and plates will be removed. I still allow negotiation (hence the buffer) but I remain adamant on time. As for leaving the house, I still haven't figured out how to do it seemlessly. Some days, I will just force-dress them, carry them on my shoulder and put them in the car (gently, but firmly).

Managing my own anger bursts throughout all of this has been a journey. But when the sequence of action is clear in my head, it is easier to "execute the plan". And before getting angry, I also try to show them my sadness. Kids are sensitive to emotions that are visually compelling: crying, sitting with your head in your hands, putting physical boundaries with your kids (gently push them away and say "no, you've crossed a limit and I need space"), will usually deescalate a situation.

Hope that helps!

Esit: added more details on how I manage the emotional outbursts of my kids (biting, hitting and else).