How do you say tag in Spanish?

"Tagging" is an American English idiom, whereas Spanish tends to hew the line more closely to the etymological tree. In this case the root is "graffiti." In Spanish "graffiti" is "grafito." Apparently there's no "official" verb for "doing graffiti" in Spanish - yet - but out in the street, they're using the made up verb "grafitar." Following the usual rules of Spanish formation, the Spanish Word that would go for "tagging" in English is "grafitando," although, like the "art" itself, it's not official yet.