To do something really badly. "To stink" means to do badly, "joint" here means a place. "Stink up the joint" is an exaggerated form meaning you "stink" so badly the whole place starts to stink, as if you've taken a shit.
"Oh no, Magnus! He blundered and lost his Queen! Okay, now I don't feel bad about my awful last game! Magnus is also stinking up the joint just like me today!" -- Hikaru Nakamura, on a stream in an online chess tournament, 13.11.2025
When a person (usually, but not necessarily, of Latin descent) who otherwise speaks in unaccented English suddenly has a very heavy accent for a Spanish word or name in a sentence.
Person A: "Hey guys, I'll be right back, I'm going to go get a PEENYATTA for Timmy's birthday party."
Person B: "Stop spicking it up John, you spent like one semester in Ibiza."