It is a somewhat old voice for headbutting, blow to the head. It has an origin in the word pumpkin, but in its popular meaning of "head" that derived in calamocha. See suffix -azo .
Porrazo, very strong fall. It can also refer to a very large slaughter during a battle, such as the one that occurred in Calamocha, Spain in the thirteenth century. Paint ochre.
Falling on the ground with force