The phrase commands a girl to engage in a sexual act in a demeaning way, using the most vulgar words possible for the act and the body parts involved. The addition of "تاپ" (top) suggests the speaker is mocking the girl by implying she is the "best" at performing this act. It is a tool used for extreme degradation and is not acceptable in any civilized conversation, online or offline.
If you typed this in out of curiosity: You’ve found the edge of the Persian internet’s dark alley. There is no wholesome meaning here—only aggression, underground music references, and a lot of profanity. The “top” in the phrase is ironic; this is bottom-of-the-barrel slang. kos kon kir dokhtar top
Please provide more information so I can better assist you. The phrase commands a girl to engage in
However, there are also opportunities for "kos kon kir dokhtar top" to thrive: If you typed this in out of curiosity: