Question #1
"Before I cum, one of my nuts gets sucked up inside my stomach.  Is that, is that, kind of like what happens before you get a hernia or something like that?"
-Prince Paul, Psychoanalysis - What Is It? Track 1: "Introduction to Psychoanalysis (Schizophrenia)

Answer:

Thanks for your question!

The answer is no, but your anatomical insight is astute.  The testicular vessels are transmitted from the pelvis to the scrotum via the inguinal canal.  Inguinal hernias occur when the abdominal contents (e.g. intestines or fat) are pushed through the inguinal canal into the scrotum. 

During states of anxiety and sexual excitement, the testicles are normally retracted into the upper scrotum by the cremaster muscle (see figure).  Exuberant contractions, such as those which may precede orgasm, can draw the testicle into the distal inguinal canal, giving the impression that it has been "sucked up inside [your] stomach."  This is not a risk factor for the subsequent development of inguinal hernia.