The most embarrassing English mistake of my life

In class yesterday, the teacher said that he would always express his gratitude to his wife who cooks.

I was going to say "The best way to say thanks to the person who cooks is to eat it all."

So I wrote:
"The best appreciation for someone who cooks for you is eating them out"

When I wrote it, I wasn't quite sure about the usage of phrasal verb, but my idea was:
run out = run out, eat out = finish, they refer to food.

As a result, the teacher blushed, hesitated for a while, and told me that I had said something very vulgar... He didn't know how to tell me what it meant, and he asked me to be very careful about what I said.

I said I don't know what I said, he said eat out means to go to dinner, but if you put a pronoun in the middle, it will change to another meaning, he said he can only say so much, he wants me to go by myself Find out what eat somebody out means.

I understood the hint at the moment, but didn't have the courage to check it out. I just said that I didn't check what it meant, but I didn't mean what he said. He said he knew.

OK, then I checked the online dictionary and found nothing.

I thought to myself, if it was really embarrassing, I wouldn't see it in these serious dictionaries, so I just googled it.

OK, what does that mean?

It means giving girls oral sex.

Worse than I thought...

Later, during the one-on-one class, the teacher asked me right away what did I mean by going to find it?
(Really concerned that I might misuse it, but can't tell me what that means, it's really hard for him.)

I said that I found it, and then I repeated the process of finding it, re-emphasizing that I really didn't mean that. 😫😫😫

I'm in the mood now that I don't use phrase verbs for the rest of my life 😂