According to a new Nixon biography, a named Kennedy aide is quoted about the following event during the John F Kennedy/ Richard Nixon debates:
When JFK arrived at the hotel, he went to his hotel suite. In order to prepare for his upcoming televised debate with Nixon, he requested a prostitute to be sent up to his room. One of his aides set up the meeting in JFK’s hotel room. JFK came out 15 minutes later, looking flushed and relaxed. This was how he prepared for the debates, and supposedly all of his televised appearances. This is how the book explains that JFK looked so calm and relaxed on television.