What should I do to stimulate the sexual desire of the man I'm interested in?
Literal
Concerning man [possessive-の] libido [object-を] stimulate [purpose-には] how-do [conditional-すれば] good [polite wonder-のでしょうか]?
気になる男性 (a man one is interested in) uses 気になる as a relative clause modifier. 性欲を刺激する is direct: 'stimulate sexual desire.' ~にはどうすればよいのでしょうか is the formal pattern for asking 'what should one do in order to...' A candid question with polite phrasing.