Me and my dad get into arguments alot and they usually turn in to physical fights, what should i do?

when we get into these fights he pushes me then i push him back and then it escalates soon were fighting and hes spitting in my face and then i always wait for him to try and hit me first, and for my self defense usualy tackle him to the ground i dont really know what else to do i just hold him on the ground and squeeze with all my might. After these confrontations he always starts talking trash and calls me names and antagonizes and it makes me mad and it usually results in another physical altercation idk what to do please help