LH and FSH are released together from the pituitary. there is not feedback loop associated with spermatogenesis that i've read of (other than nocturnal orgasms when there is too much). so spermatogenesis and test production should be shut down together (if they are going to shut down at all). and that depends on you. i personally have a hard time shutting down anything, and my nuts stay almost 100 percent throughout the cycle (i'm on dbol now actually and my loads are thick and creamy, just the way my girlfriend likes it on her face), but other bros aren't so lucky. it's quite an individual thing.