an acronym, commonly used on the Internet, meaning "holy shit, dude", derived from the infamous South Park feature film, 'South Park: Bigger, Longer, & Uncut' quote - Kyle Broflovski
Mr. Garrison: What did you say?!
Eric Cartman: Oh, I'm sorry, I'm sorry. What I said was: How would you like to SUCK MY BALLS, Mr. Garrison?
Kyle Broflovski: Holy shit, dude(HSD)...
High Sex Drive.
Normally owned by males who masturbate to much. Can end in death of their girlfriend.
Unless the girl has it too...
Boy: Come here, *Grunts* Ooooh more.
Girl: Fuck stop that hurts!
Boy: You like it!
Girl: Stop! You have HSD...