Another way of saying something or someone is "hardcore". In reference to the candy bar, which has a hard candy core.

When a guy shoves his fingers up his cornhole, so that he has a large amount of dookey or shit smeared on his hand. He then masturbates furiously, so that the his penis is smeared with shit, looking similar to a heath bar. He then gets his girlfriend/boyfriend to give him a blow job, tasting like a delicious choclate bar.