A person that, due to risky sexual behaviour, have more STDs than your local streetwalker
"... if the girl keeps insinsting on fucking without a condom you can assume she fucked a lot of guys who wouldn't use condoms in the first place. You'd basically fuck a stdclopedia" - random dude in 9gag
A term used as a way to describe a song that consists of sexually-explicit lyrics, typically to a degree where mentions or depictions of sex are constantly sung in the song. Some examples include:
"Make U Cum" by Ayesha Erotica
"Girls" by The Dare
"WAP (feat. Megan Thee Stallion)" by Cardi B
Person 1: "Did you hear that new single from The Dare?"
Person 2: "That song is so STDcore."
12 step recovery jargon referring to someone new who talks about how great life is, now that they'resober. Usually meaning that the person is out of touch with reality.
The new guy seems pretty happy for a dude who has no job, no money and no family. He must be on a pink cloud.