Retrasame comes from the verb retrasar, meaning 'to delay' or 'to postpone'. The -me suffix means 'for me' or 'to me', making it a command: 'delay for me'.
In the song, the singer is pleading with his beloved not to leave him, even for one more night. He dramatically asks her to "retrasame la muerte" (delay death for me), using hyperbole to express the profound impact her departure would have on him. This intense and poetic use of the word makes it particularly memorable and emotionally charged.