What is a safe way to grow your penis?

No such thing. Safety and penile enlargement do not belong in the same sentence. Sorry to burst your hopes. Maybe in the near future?
Penile growth. The best way is to enter into a loving relationship with a partner who cares about you and is able to have an open and honest relationship with you. Men need to be honest with themselves and their partner and get over penis size. There is no safe way to increase penis size. You have what god gave you!