This is the 8479th most frequent Dutch word.
harses
"Harses" is Dutch slang for "head" or "brain."
In this sentence, 'harses' is used colloquially to refer to 'head'.
Mijn harses doen pijn van al dat nadenken.
My head hurts from all that thinking.
Here, 'harses' is used metaphorically to indicate 'mind' or the seat of thought.
Ze kreeg het eindelijk in haar harses om op vakantie te gaan.
She finally got the idea in her head to go on vacation.
In this example, 'harses' again refers to 'head', emphasizing physical impact.