Nonseminomas are actually a group of cancers. They include choriocarcinoma, embryonal carcinoma, teratoma, and yolk sac tumors. It is the involuntary ejection of semen during sleep. It is a normal, healthy occurrence brought about by the accumulation of semen in a male who does not have sexual intercourse or does not masturbate. During adolescence, a nocturnal emission is usually associated with an erotic dream.
Wet dreams are part of the many things that are changing in the body during puberty.
Not all boys have wet dreams and that's normal too. However, if you do have a wet dream all it means is that your body is sexually maturing, which is a step towards becoming a man. A wet dream is the uncontrolled ejection of fluid from the penis during sleep. The fluid is creamy or clear in colour, not like urine. Sexual excitement from dreams or by physical stimuli like rubbing against pajamas or a full bladder.