Mr Evans, 56, allegedly molested the complainant by putting his hand inside his boxer shorts as he slept at the MP's house in Pendleton, Lancashire, in July 2009.
A meeting was arranged with Patrick McLoughlin, then the Tory chief whip in his House of Commons office, Preston Crown Court heard yesterday.
The young man claimed he told the MP, along with John Randall MP and Iain Corby, a Tory policy researcher, that Mr Evans should resign as an MP.
Mr Evans, 56, denies all charges.
The trial continues.