I voted for the testicle, as I use the pinkies.
I think it depends on the circumstances, I think I could live without a testicle better than I could a finger. But only if it was surgically removed. If I were to lose one as a result of an accident, I would want to lose the pinky. Has to be less traumatic.
I think my golf game would fall apart without my right pinky. I use the interlocking grip. Right pinky interlocks with left index finger.
If I were to lose one digit off either hand, it would be the left thumb.
I dunno. You really need your opposable thumbs. What is it you do with your pinky that can’t be made up for with the other fingers anyway?
I’m the opposite. I would rather lose all 3 testicles than a part of any finger.
Rather than the answer, I am intrigued by the hypothetical situation that brings about this “half a pinky, either hand your choice or a testicle” decision. Abducted by Criminal Minds style psychopath? Angry spouse? Drunken wager? Bored and just bought a really sharp hunting knife?
I thought we’d answered that on the first page: a really cruel version of “Let’s Make a Deal” 
At least the OP didn’t say: “Need answer fast.”
Wonderful.