With the gaydar, gay men supposedly recognise other gays from a group of men.
The Gaydar (or the "Gayradar") is supposed to enable gay men to recognise other gay men from a group of men. A special advantage! After all, sometimes embarrassing situations (when flirting with straight men) can be avoided. Of course, there is no classical sense that could be called "gaydar".
Rather, those affected usually have good powers of observation and recognise gay people by the way they talk or behave. After all, there are different types of looks or actions that can indicate that the person opposite is gay could be. This is exactly the aspect that men take advantage of with a gaydar.
By the way: there are of course also women with a gaydar! This supposedly prevents them from approaching particularly attractive gays from time to time.
Of course, however, an integrated gaydar can certainly strike wrong. After all, there are also many men who straight but are characterised by some feminine attributes. Here it is important not to infer "gay" or "not gay" from an overly high-pitched, feminine voice or certain gestures, for example. Otherwise, prejudices are merely served here that do not always stand up to reality.
Some gays love to play with the rash of gaydar. They deliberately act gay - especially in larger groups with straight people - in order to catch the eye of potential flirting partners. Of course, there is nothing reprehensible about this. On the contrary! Such behaviour makes it possible to get in touch with like-minded people in a comparatively uncomplicated way and (more or less) discreetly draw attention to oneself.