You would not believe your eyes

Drugs.
Because why else would fireflies be giving you hugs?

Each bug hugs him 1000 times. That's the answer

That was my jam boi. And the music video was rockin too

The real question

It's most likely the second one because it states in the song "as they tried to teach me how to dance" meaning the purpose for their contact was for teaching and any hugs were accidental

Please take me away from here

But they're not real fireflies. They're supposed to be a metaphor for his racing thoughts as he tries to fall asleep. And the fact that he gets a thousand hugs from ten thousand lightning bugs seems to mean that he can only grasp a few thoughts out of the thousands.

There are no hugs. The fireflies are trying to crush him to death with their powerful claws.