Definitely a chilenism, also in a more slang form "chanta un ope en la latu" (chan-tunopen-lalatu)
"chanta" is the imperative form of chantar:
1. Stop something that moves suddenly (i.e. "chanta la moto" -> stop the motorcycle)
2. Put something forcefully (i.e. le "chantaron el medio combo en el hocico" -> he got a huge blow in the mouth)
Meaning:
Literally a prompt to someone to fart on the very proximity of the penis of the person saying this sentence in order to facilitate the anal penetration.
As a figure of speech: a public accusation of homosexuality
Used in Chile as well
"Chantu nopen lalatu sapoi la conchetumare"