Cum is a vulgar slang word for the liquid that comes out of the penis during ejaculation. Sometimes spelled come, this is very inappropriate word.
When a man cums, he produces cum: this word can be a noun or verb. But the most important thing to remember is that this word is very obscene and inappropriate. Technical words like semen and seminal fluid — or even softer slang like seed — are not considered as nasty. The spelling cum is often used in pornography.
