A "Roberto" is slang for any infection incurred from sexual practice. This includes STD's, as well as infections from contact with fecal matter, from example.
"Had an awesome time with that chick last week but I ended up with a Roberto".
He’s a guy named Roberto , he thinks he has a big dick and he has a fuckable face! He likes tacos and eats them everyday ! And he likes being called papi , and he’s Mexican and his grammar is really bad and needs to stop ditching class and thinking he’s cool