My ex-boyfriend Fred grew up on a farm, where every summer the hogs born that spring would be castrated, and the testicles -- aka Rocky Mountain Oysters -- were breaded, fried, and served for breakfast, along with pancakes and syrup. You could also eat them with ketchup, hot sauce, or cocktail sauce.
They have about the consistency of scallops, without much taste of their own. Not really a big deal, except for guys who get queasy over the thought of chomping down on something that used to be part of a hog's genitals.
Generally they are advertised by horrific puns, like "Come and have a ball. If you miss it, you're nuts." The one in Texas has an evangelical Christian focus, so it tells you to "Come and have a ball with Jesus."
I've been to the "original" Testicle Festival, held every summer for the last 32 years at Rock Creek Lodge in Clinton, Montana (there are daily shuttles from Missoula, if that helps).
You'd expect a festival dedicated to male sex organs to have some gay interest.
Hard-bitten redneck women in cowboy hats pretending to be surprised at the size of their partners' penises.
Hard-bitten redneck men in cowboy hats who aren't having nearly as much fun as the women, and don't flash their penises very much at all. There's a little male nudity, but mostly of scary guys.
There's a wet t-shirt contest so you can see ladies' breasts, but many of them go topless anyway.
The website advertises "The Hottest Bartenders." Lady bartenders, that is.
There is no indication anywhere in the festival that any man might want to look at another man's "big balls."
You'd be better off buying some of your own from the Exotic Meat Market. They sell USDA-approved testicles by the pound: bull/bison/veal ($20), wild boar/lamb/goat/elk ($25), duck/yak ($30), ostrich ($50). Get several kinds and have a buffet.