It's a game of words, since "Tabar" comes from tabarnak, used as a swear word and insult, second is "naco (fmn naca)" is a pejorative word often used in Mexican Spanish to describe bad-mannered and poorly educated people.
"Ya sabes como son estos tabarnacos, son mas nacos que tabar"
"Los tabarnacos son bien chistosos"
A person (a closeted homosexual) who tries to be as good and "clean" as humanly possible. he/She is more often than not a staunch conservative and takes pride in its virginity and practice of abstinence. He/She is definitely a God-fearing homosexual or lesbian who cannot abide it when people cuss in front of her–the most extreme goody two shoeses faint when hearing foul language–and of course He/she would never consider smoking, drinking, doing drugs, or having any physical contact with a boy or girl (respectively) beyond holding hands or perhaps a kiss on the cheek. Can be nice but eventually begins to lecture you about your "sinful" lifestyle and just becomes a pest.
"Eduardo Verastegui (previous Ricky Martin's love) is a Homo-Goody two shoes"
He acts so much like a nun, he's a Homo-Goody two shoes