Deedo Hibiki <deland@club-internet.fr> wrote:

He had been thinking about a lot of things laying in the park. All the
misunderstandings, the fiancees, his enemies, his mother and all the
troubles that had been plaguing his life lately. The outcome of all
those reflections were bad for his self-image.

I *think* "laying" is wrong, but I'm not 100% sure of the correct form.

Well, I don't know for sure either : I've looked into my dictionnary,
and it seems to be the right form. But it DOES sound weird.

It should be "lying." "Laying" would be used if he were doing it to
something else, e.g. brick-laying, or a han laying an egg.