I can give you the real answer. Most people have no idea and use the words wrong all of the time. Yet, the world still moves on and we manage somehow!
I love language and grammar, but I am not a huge grammar pedant.
The forms of the verbs almost feel irrelevant.
For example:
lay means to "place something down flat" (to put or set down)
lie means "to be or to stay at rest in a horizontal position usually on a flat surface."
The problem is that the past tense of "lie" is the present tense of "lay." Few people use lay when then mean past tense of lie. It sounds weird.
I lay down on the couch for an hour or I laid down on the couch for an hour.
I hear the second one far more frequently than the first.
Is the universe and Standard American English Grammatical rules trying to tell me that I am unable "put or set myself" down physically somewhere? And is it possible to lie down in a non-horizontal position?
Can I say, "He lay asleep?" Lay is the past tense of lie. What stops. The sleeping or the laying? ha!
I think people might say asleep is acting like an adjective there describing his state of being.
That means he is no longer sleeping. and he is no longer laying.
If I wanted to say that and he is currently sleeping would I then need to say, He lies asleep? present tense.
You can't lie yourself down.
Yourself acts like a direct object there.
The verb lie is intransitive. It is like sleep. It does not take a direct object. So, if you use a reflexive pronoun, you actually want to say "I am going to lay myself down" or "I am going to lie down."
How you know the difference between lie and lay is if the verb takes an object. Lie does not take an object. If you are placing something somewhere, then use lay. The thing you are placing is the direct object.
And it also sounds weird to say "He is lying down for an hour" or " I am lying down for an hour."
"I will lay down for an hour" I think people use "lay" and "laying" there.
That is what happens when the past tense of a verb is the present tense of another. And a common form comes up when we want to talk about truth.
"He is lying!"
"Well, tell him to get up!"
"No, I mean he said something untrue."
"Oh, well what kind of fib did he lie on you?"
"You mean lay. He laid a fib on me."
"Wait, what? You mean you are using the transitive form of lay in a slang fashion that means "to tell someone something? I need to know all the grammar.
Lay it on me
English really should have fixed this one a long time ago.