If there isn't alot of meat on the bone, I'd just boil the shit out of them, use the stock, pick off the meat, add a ton of spices, extra garlic always works good and just nibble away.
I see them in the butcher case every time I'm in and they just look like more work, not enough meat.
See what Google has to say..
I'm trying to track down some Bull Testicles, just to say I tried them..........
Good luck, report back.