Reruns of “SpongeBob SquarePants” flash across the living room TV, lighting the faces of the parent and preteen child sitting on the couch — until 8 p.m. rolls around and Nickelodeon becomes Nick at Nite. Programming turns from cartoons to ’90s nostalgia reruns, and all of a sudden, there is a lot of S-E-X talk.

The first show that comes on is an episode of “Friends” wherein Phoebe asks the group which they would rather give up — sex or food. And every time the characters say “sex,” it feels like they are hammering both of you over the head with it. Finally, Joey says, “I want girls on bread,” and because this statement can be silly to anyone who knows what sex is and confusing to anyone who doesn’t, it sparks a conversation.

The spring of puberty is upon the preteen, and they have questions. A year or two prior, this would not have been an issue, but now that their curiosity spikes on all things sex, discussions on the topic could take place at any time.

But this does not have to be an issue. Talking about sex can be a natural, casual conversation, and the Chronicle spoke with communication and sex experts to find out how to begin those discussions, whether you are the parent or the young adult.

If you are the parent:

Using an example of something you heard from media like “Friends,” or even a song or magazine article can be great entry points to the conversation, but parents should start communication about sex from the beginning with the correct words to refer to body parts, said Sylvia Mikucki-Enyart, associate professor at the University of Iowa in the Department of Communication Studies.

“It’s a penis. It’s a vulva. Then you could talk about how there is the vagina as well, your scrotum, things like that — using proper terminology, not using nicknames or euphemisms,” Mikucki-Enyart said. “For instance, our [8-year-old] son has asked how babies get created, and we’ve talked about the sperm and the egg and even fertilization.”

You can even begin these conversations during babies’ bath time, letting them know what you are cleaning, she said.

Catalina Lawsin, Ph.D., a clinical psychologist, specializing in sex and relationships at her private practice, said your first steps to sex talk depend on how emotionally mature your child is. You can begin talking about topics like consent and boundaries, and that can lead to conversations about how they would like or not like to be touched.

Lawsin said to think about what kind of vocabulary your child already has and gradually introduce new information. Children grow and learn at different paces, and she said assessing them at an individual level when teaching them about sex is important.

“Start off just acknowledging, ‘Hey, you know, it’s pretty common that kids have questions about sex,’ or ‘There’s a lot of confusing information out there about relationships,’” Lawsin said. “Making those normalizing statements to just say, ‘Hey it’s okay to talk about it.’”

Mikucki-Enyart said when children enter their teen years, talking about pleasure is important, especially for female-bodied individuals, whose pleasure often goes ignored. She said to begin talking about STIs and protection, as well. If you make this part of your dialogue like it’s not a big deal, having these conversations will be much easier.

If you are the young adult:

Mikucki-Enyart said if you are a young adult who wants to ask their parent about sex, you can be direct and ask your parents outright what sex is, or you could be more indirect and say something like, “Someone at school today was talking about something called a blowjob. What is that?” or “Someone was talking about people laying on top of each other, what were they talking about?” Although, she would recommend the direct approach if you want more direct answers.

Lawsin said if sex is taboo in your family, you can build up your confidence by practicing asking questions before you go to your parent.

Or if you do not feel comfortable or safe talking with your parents about sex, your doctor may be able to answer questions, Mikucki-Enyart said. At a certain age, your doctor may even ask your parents to step out of the room to see if you have anything you need to say privately.

“These don’t have to be embarrassing [conversations],” Mikucki-Enyart said. “When parents make it feel like it’s embarrassing or they don’t talk about it, then it becomes something that’s taboo that maybe we feel dirty and shameful about; so if you bring these conversations out into the open, just like we would talk about anything else, it really takes the stigma away from them.”