I made the mistake of responding to the email with a dictionary definition of "twink".

"twink
/twink/ [UCSC] may derive from gay slang for
a cute young thing with nothing upstairs (compare mainstream
"chick")."

He wrote back with this response which really sounds like it's from a cop:

"Does it ever mean underage? The reason I ask is that "chick" could mean girl, if you look up that at dictionary.com"

DO NOT RESPOND TO THESE TYPE OF EMAILS!