I'm so glad it made you squirm! The surgery scene was probably the hardest part of the game to write, trying to land the right tone through a reasonably accurate description of actual gelding, so I'm really glad it's working for people.
(Adult) Summertime's eyes are taken from a photo of a young Walt Whitman (and then colored and skewed and generally messed up), one of those details that's mostly just there for me. I knew going in that I wanted him to have disconcerting human eyes, but then the themes and the selection from Song of Myself all coalesced, and it had to be Walt Whitman.
We've gotta resist. Even if it's all we can do, we can't be the good horse.