A dominatrix at the Rapture S&M parlor in TriBeCa allegedly offered a "prostate massage" to an undercover cop for $200, leading to her arrest Monday night on prostitution charges. The 21-year-old pleaded guilty to disorderly conduct and was conditionally released. The owner of the club, Staten Island's Collin Reeve, was also arrested and charged with promoting prostitution. His lawyer tells the Daily News that "the NYPD does not know the difference between prostitution and freedom......