What does it mean when a boy comes?

Answer 1

I assume you mean "what does it mean when a boy has a climax?" - in this case, it means he has achieved an orgasm through sexual behavior. This is an enormously good feeling, and most people will tell you that it is a good thing to do. However, there are risks - many, but not all, orgasms may occur while the penis is inside the woman's vagina. This could result in pregnancy if the woman is ovulating, or just about to. Also, some STDs are transmitted in semen (or in any bodily fluid, like saliva or blood as well). The wording of this question appears to lead to the conclusion that you may be rather young and/or immature, so I would be very careful about your curiousity in this matter.