Tatamí refers to the mats used in martial arts like judo or karate. It's a very specific and somewhat unexpected word to find in a rap song about love and heartbreak.
Charles Ans uses it metaphorically when he says, "Si voy a dañar mi orgullo va a ser dentro del tatamí" (If I'm going to damage my pride, it will be inside the tatami). This implies that if he's going to suffer or fight for his pride, it will be in a controlled, almost ritualistic space, like a martial arts arena, rather than in a messy, public display of emotion. It's a unique and intriguing image.
Charles Ans originally planned for "Aquí Todo Esta Bien" [Everything is Fine Here] to be the saddest song on his album, but as the title suggests, he decided to change course. He's trying to convince himself (and maybe us) that he's doing okay, even though he's clearly still dealing with a past relationship. He admits, "Hoy voy a tomar para no pensarte mami" [Today I'm going to drink so I don't think about you, mami] and says, "Solo se que te quiero aunque me dañes cual tsunami" [I only know that I love you even if you hurt me like a tsunami].
He's trying to move on, but it's tough. He mentions how it makes him feel "tan pobre, que estés con otros hombres" [so poor, that you're with other men] and how all the success he has now "me sabe a cobre" [tastes like copper]. He's trying to forget her, even asking for "tiempo para abrir otra cerveza / Para ver si me emborracho y te sales de mi cabeza" [time to open another beer / To see if I get drunk and you get out of my head]. Despite the pain, there's a glimmer of hope at the end, with the line "Recuerda tras la tormenta llega la calma" [Remember, after the storm comes the calm]. It's a relatable journey of trying to heal and find peace after a breakup.