Well, why can't you have a third person lying under the bed, never seen or heard?

You would just see one end of a person lying on it.

I can tell when a person is lying without it.

It would be better to help the person lie down.

If possible, the person will lie down to go to sleep.

"When it was over, I saw one person lying on the street."

A person, a male, is lying on his back listening to a voice telling him about the past, the present and sometimes the future.

The other person could have been lying to my friend.

The researchers found that after being friends for six months, men in the study were still unable to tell when the other person was lying.

Well, if that person can't lie and has knowledge of the truth, then they're a filter.