MOONLIT BREW CHAPTER 2 PAGE 16

Now i didnt quite think it was fair for Lydia to hit poor SImon; She could have chosen to avoid telling anything even relevant that could lead to that exact detail but she instead chose to bring it up.

Also, on that note, since she did, its good to know that transforming (or going floof) is somewhat equivalent to pleasuring yourself; And on a different note, the logic sorta makes sense.

I mean, when your physical anatomy is morphing from the inside out, i would imagine that it would be rather painful, so as a natural reaction, the body would release that "Feel Good" chemical in the brain to counterbalance pain that could kill you.