a regular "guy nextdoor" who has a certain affinity for wild, unabashed sexual activities. You never know what he's going to think of next, as his creativity in bed is without limit. Relates to the Marvel comic book villian "Juggernaut", who has been deemed as "unstoppable".
"I slept with this guy the other night. I have been defeated, and remain in ruin. What will he think up next? As they say, you just can't stop the douggernaut!"
"Oh my gosh...I had some crazy sex last night. This dude is a regular douggernaut!"