It is the phrase "to be up to the cojones" without the spaces. See cojones ("testicles").
BEHASTALOSCOJONES to be up to the toes, to be pissed, to be tired, to be up to the head, TO BE UP TO THE COJONES, to have the balls swollen Some synonyms, words or similar expressions may be up to the tusa, to be bored, to be desperate, to be tired