What does it mean?
"He could hardly keep himself from running out into the thick of the action to play with them"

I didn't understand what "run out into" and "thick" mean.

Question

What does it mean?
"He could hardly keep himself from running out into the thick of the action to play with them"

I didn't understand what "run out into" and "thick" mean.

Answer

in the thick of the action = in the middle of the action
----where there are lots of people so it looks "thick".

Answer

The "thick of the action" is in the middle of it. For example, if it was a soccer game, to "run out into the thick of it" is literally to run and get right in the middle of the game.

Answer

He wanted to be in the middle of the group