Balls
Tubing
Anything else?
Balls aren’t cubes (typically), so they dont fit together flush. So what fills the gaps?
Oh, about tree-fiddy.
Also fluid to keep everything suspended and lubricated. These fluid-filled regions can swell to outrageous size in a condition called a hydrocele, which , if it doesn’t go away on its own, requires an operation to reduce.
Your correspondent speaks from recent experience. Ouch.
The wikipedia cite includes “ballsack” and “ballbag” but completely omits “nutsack” and “cobbler’s purse”. I have remedied.
I am shocked that inside one of my organs of masculinity I have something called a ‘tunica vaginalis’.
Well, it’s very very complicated tubing, with separate names for all the different sections, plus various membranes and layers on top of the testis itself, all of which are very important for messing with the minds of anatomy students who must regurgitate the names on exams.
Yes, but to counter that there is a layer of deep connective tissue in the penis called “Buck’s fascia” which is a very masculine name, if you ask me.
Jackmannii, who once lectured to medical students on pathology of The Penis and The Testis, and is thus an expert on such matters. 
Interstitial cells.
What are you asking us for? Go grab a flashlight, put up your legs and stretch out your nether bits and check it out yourself!
I picture a lot of head turning and coughing in that class.
You assume the OP is male. Maybe this option is not open to her.
I don’t want Buck’s face anywhere near my boys, especially an Italian named Buck.
And what about teabag? The page is blocked. :rolleyes:
The diagram on the wiki page shows a lot more non-ball meat in the sack than I was expecting: muscles, cords, etc. The sack is pretty well fully occupied. The scrot is also apparently arranged to conform to the shape of the contents, like vacuum sealed meatballs: not a lot of free open space in there. I was imagining something more like this bag o’ marbles with some voids to fill with something (other than a third marble).
There was an episode of the BBC show Embarrassing Bodies that showed one of these hydroceles being drained. It’s an image that won’t soon leave me.
Cursed as I am with a tendency to literal visualisaton that just serves you right for your user name.
This is more or less how docs diagnose the aforementioned hydrocele. The fluid in the scrotum refracts the light in such a way that the entire scrotum glows. At least that’s how mine was diagnosed back in 1981, just after graduating high school.
Does scrotal fluid have a name?
That’s what I was told, so I gleefully got my Maglite – the big three-D cell one, and turned it on. I was severely disappointed with the results.
I salute your efforts in the fight against ignorance.
Bummer, all mine did was cast a rainbow on to the side of the refrigerator.