My teacher at school says: You need intimacy for sex. What is that: Intimacy? And where does it come from during sex?

Intimacy is a difficult word.
It means: You trust a person very much.
And that person also trusts you.
You are not embarrassed in front of that person.
When you two are alone together, “intimacy” can develop.

When two people are in love, that means:
They are close to one another.
They look into each other’s eyes.
They talk in low and tender voices.
They touch one another and perhaps caress one another.
Sometimes, both people get in the mood to have sex with one another.

But that doesn’t always happen.
Sometimes one person just wants to cuddle.
That means: The person is satisfied and doesn’t want to do anything else.
Important: Both only do what they want to do.