why is it that the "third testicle" get bigger at times?

[MikeyG]

i think you play with your balls too much

 

[Zoomster]

As long as this "whatever it is" thing in your sack is changing in size, then you are probably referring to the items listed above. If it isn't then you need to be examined. As far as Docs cutting items off of the testicles is concerned....usually they take the testicle. Very rarely will they cut anything off of a testicle.