Need advice

I have a 12 year old son. As most people know kids at this age are getting their puberty early. My son ask me today when he can start shaving his penis and I didn't know what to said to him. He said the hair are long and sticking out. My husband is not his father and he only been around us for 3 years so he doesn't feel prepare for this situation even know he has a son younger that one for just one year. What can we do as parent to discuss this situation with my son?