Use the proper names of body parts

Just as we teach children that a nose is a nose, they need to know what to call their genitals. This knowledge gives children correct language to understand their bodies, to ask questions, and to tell about any behavior that could lead to sexual abuse.
Here is a one-page document that breaks down the importance of using accurate names of body parts.

Teach the difference between safe and inappropriate touches

For younger children, teach more concrete rules such as “talk with me if anyone - family, friend, or anyone else - touches your private parts.” Some families use the "health and hygiene" rule - touching private parts is only okay when it is by a parent, caregiver, or doctor, and only to keep children clean and safe (or healthy and hygienic). Also teach kids that these rules apply to them. They should not touch other's private parts. Tell kids that private part touches are never okay even when they or other people use threats, special treats, guilt, or other tactics. ​

Respect a child's right to learn about and understand their bodies

It is natural and normal for children to explore their own bodies. Many children discover between the ages of two and six that their private parts may feel better or different than other parts of their bodies. This can make adults uncomfortable. It can be helpful to remember that children are learning how their bodies work. It's not 'wrong' or 'dirty'. Help them understand that those feelings and touches are okay, but they may also be private, like using the toilet. 

Children may also explore their bodies with other children. Sexual play that is safe and normal is usually:
    Between children who have an ongoing mutually enjoyable play and/or school friendship.
    Between children of similar size, age, and social and emotional development.
    Lighthearted and spontaneous. The children may be giggling and having fun when you discover them.
 
When adults set limits (for example, children keep their clothes on at day care), children are usually able to understand and follow the rules.