Bravo insiders are snickering about an expensive ad campaign green-lighted by network president Andy Cohen hitting New York buses, phone booths and taxis — featuring the perma-tanned face of, you guessed it, Andy Cohen. One told us, “It’s all about Andy Cohen. Even though Season 4 of ‘Real Housewives of New York’ is about to start on April 7, the ads to promote Cohen’s show, ‘Watch What Happens Live,’ are all over town.” A Bravo source said the campaign will appear here and in Chicago and was green-lighted by the marketing department. Bravo declined to comment.