Sponge Head is a slur used to describe Blacks in a derogatory way. African's naturally bouncy/kinky hair, when uncut, tends to be big and poofy when dried out. When you sqeeze it it seems as if it would bounce back at release
The word Sponge Head is a racial slur that has been used historically to degrade and dehumanize blacks. The word is still used by some people for this purpose, and it is seen as offensive and hurtful to blacks. If you are unsure about whether or not it is appropriate to use the word Sponge Head, it is best to err on the side of caution and avoid using it in any situation.