Erfinderisch translates to "inventive" or "resourceful". It's a less common adjective in everyday German, making it stand out in a song.
In the context of the song, the singer says, "Denn Babe, in deiner Nähe werde ich erfinderisch" (Because, babe, near you I become inventive). This line beautifully captures the feeling of being so smitten that you'll come up with creative, perhaps even silly, ways to impress someone. It's a charming and relatable expression of new love.
The whole song is one moment stretched out: someone walks towards you and your body reacts before your brain does. "Und mein Herz macht boom" [And my heart goes boom] is the title doing the work, and CRO builds everything else out of the same reflexes. "Meine Blicke wie Magneten auf dich drauf" [My eyes on you like magnets] is less a compliment than an admission that he can't look away, and then the confidence falls out completely: "Doch ich frag' mich grade: Siehst du mich denn auch?" [But I'm just wondering: do you see me too?].
The second verse is where it gets funny. "Und um dir zu gefallen, mache ich irgendetwas Kindisches" [And to please you, I do something childish] is an honest thing to admit, and the big romantic gesture right after it, "Schließ' meine Augen und ich mal' dich mit 'nem Pinselstrich" [I close my eyes and paint you with one brushstroke], falls apart a line later into "Doch kommst du mir zu nah, wird mir schwindelig" [But if you get too close, I go dizzy]. The hook isn't even words, just "Uhh-uhh, uhh-uhh-uh", which is roughly the level of speech he has left.