The protagonist (male or female) of that game is crossdressing and has to keep their crossdressing under wraps, otherwise there will be consequences. The most common example is when the protagonist has to infiltrate an all-girl school and for that is forced to crossdress. Another example would be when the protagonist likes to crossdress but doesn't want people to know, because they will be mocked if discovered. Do not tag games where nobody knows the protagonist crossdresses, but this state is not the consequence of the protagonist actively trying to deceive people, just the consequence of a convincing crossdressing. Do not tag games where the secret is exposed early on.