Chongo in River Plate region is used as follow:
Uruguay_ 1) Male prostitute that acts usually as the active part or top, they are generally young under educated males with good bodies and well hunged
2) A male person who is poorly educated, with bad manners, a cheezy taste in clothes and hairdos(usually the most important is showing off a Nike pair of shoes). They listen to cumbia, specially cumbia villera and latin comercial booms as reggaeton. In this way you may also say chonga for females but in this case is most used as cheap whore or slut. Some synonyms are terraja and guiso (guisa for female).
Argentina- Mostly in Buenos Aires is used to name masculine acting homosexuals and rarely to refer to male prostitutes
Uruguay: How much did you pay for that chongo yesterday?
Look, what a hot piece of chongo over there!
Come on! You can´t be looking at that girl! She´s such a chonga!
I´m sorry but your new boyfriend is such a chongo! Teach him to speak and dress properly if you want to introduce him to your parents.