Thanks for your question! Cum is a slang word for the liquid that “comes” out of a guy’s penis when he ejaculates.  The real name for this fluid is called, “semen” or seminal fluid.” The release of semen typically happens with “orgasm” (a pleasurable sexual feeling). Semen is made up of sperm, fructose (a sugar), proteins, amino acids, enzymes, citric acid phosphorus, potassium and hormones called prostaglandins.​