Otaku-kun no Seiheki wo Isshou Yugamete Iku Ishuzoku Musume-tachi - Ch. 8 - TS Sweet Shrimp Girl testing the Theory that Lower Arm Feels Like Tits.

[raze2012]

It was never a fetish.
Something like "liking your friend that used to be a guy but is now a girl" is just being straight. More a sub-plot than anything.
Gender bender ends up being a plot device.

Liking your childhood friend Onee-San is also being straight. You can still argue that older woman or older sister is a certain type of fetish.

And yea i guess most fetishes do tend to be the plot device, since that's what the work is focusing on.