A guy cross-dressess so a woman doesn't have to be the bait.
This is when a guy goes undercover by crossdressing, even though there's a woman present who can do the job; whether it's due to Rule of Drama, or Rule of Funny. And usually invoked in, but not limited to, Cop Shows. Sometimes, during a sting, it may become necessary to go undercover. Perhaps as a client, or as the seller, if the buyer is who they're out to collar. Or, they may try to blend in by posing as an Innocent Bystander. The important thing, is to catch the criminal in the act, get the evidence, and make the arrest. But in this particular instance, the perp isn't out to buy drugs, illegal weapons, or Black Market merchandise. What they're after, is a woman. Thankfully, the hero's in luck since some of their fellow officers, or their friends, happen to be female and capable of handling the job... except they won't do it. Just because they can kick all sorts of ass doesn't mean they're okay with being the bait for some lecher, or worse: a rapist. What if something were to go wrong and backup doesn't arrive in time? The idea of being alone and at their mercy, possibly with no way to signal for help, would be enough to make anyone hesitant. Which is why the hero may not allow them to take the risk in the first place. After all, Women Are Delicate and meant to be protected, no matter how strong, or skilled, they may be. Doubly so, if the female in question happens to be their Love Interest. Still, they can't just show up as is. They need a disguise, if they're gonna be the bait. Which means, they've gotta "dress" for the part. Literally. In comedy settings, however, it may be a case of the guy being Dragged into Drag. Especially if their female friends rope them into it for their own amusement. Bonus points if the result is a Paper-Thin Disguise and the perp still falls for it. When adding examples, be sure to explain how and why the guy ends up crossdressing, despite a female being present, which is the core aspect of the trope. A real female would be more effective as bait, than a guy in drag and, since the trope requires that one, or more them, be available, it makes it unnecessary for the guy to crossdress at all. Yet, the narrative makes so they will.
ExamplesAnime and Manga