This is not a crime

It is a "violation" see NY penal code 245.01

http://law.onecle.com/new-york/penal/PEN0245.01_245.01.html

Exposure vs. Public Lewdness newyorkcriminaldefenseblawg.com/tag/penal-law-section-245-01/

Explaination of violation vs. crime
http://www.newyorkcriminallawyer-blog.com/2009/02/new-york-criminal-defense-law.html

Public defender (government lawyer) should be good enough. I would not hire a private lawyer. But again like I said, it depends on whether your friend cares about his record or not.