Com on, man, you're old enough. AND you're from South America. The girl makes him horny.

This is slang. It means she's getting her male friend horny.

She excites him and he can't stop thinking about her.

I assume you mean the song released in 1964 by Ray Davies and performed by his band, The Kinks. The song is titled "You Really Got Me". The song starts, "Girl, you really got me goin'"" To put it politely, the lyrics imply an infatuation with a girl. The lyrics also say "You got me so I can't sleep at night". You get the idea.

This is an old song. the song explains itself. Giiiiirl you got me goin' now, you got me where I can't sleep at night. You got me where I don't know what im doin'. Or some such.. She is what drives his mind; an obsession he enjoys.