Well, you could increase the entertainment value of the device by attaching thumbtacks to the paddle (point side up, of course).
Then when the unsuspecting fluff goes up the ramp and and takes the bait, bam!
PROFIT
The trigger plate could also drop away so the fluffy faceplants, and this would give the optimal angle for a nutshot.
Also, plastic and/or disgusting sketties.
simple solution, add a cage suspended below it
A sticky solution on the pressure plate may also be fun. They pull and pull and get smacked and smacked.
Maybe add a small camera nearby that starts recording when something moves around the base and turns off after a minute if the trap doesn’t trigger.
Give it a speaker set to play a studio audience / series of various laugh tracks on loop when the trap triggers.
Clip the series of victims into a montage video.
Another option is to simply increase the force of the spring to pulverize the fluffnuts. You’ll probably shatter the pelvis too, which adds to the good times.
I could definitely see a montage video like this being a hit in Fluffyverse’s Youtube. 
ouchie ouchie goes special wumps
“Oh! You never specified that!” Seriously had me laughing out loud. I actually showed this one to my wife, cuz I thought it was so funny… she, uh… isn’t exactly a member of the fandom. But that’s how much I love this one!
Even if they don’t get captured, it’s highly unlikely that they’re having any more babies.
FATALITY
Fluffy goes flying off screen at 119% smash bros announcer"game"
Damn. Good on you for having the guts to show it outside of the fandom.
To be fair, I doubt the fluffy will be going anywhere anytime soon. I’d consider it captured.
And that solves the capturing issue too!
I’ve shown it and explained it’s history to a few people. But those are people who understand the kind of vile, disgusting reprobate that I am.
Hmmm… Studying this trap… Its pretty humane… It.will neuter the males on the spot… Or damage them to being sterile… Can’t reproduce, and certainly will affect feral population, and not have to find dead ones constantly… Nice job!
Should name the trap “the nutcracker”