Undertale - sans, das gay.

FANON SANS: hypersexual, depressed skeleton
CANON SANS: "i'm gonna make a pun"

In all honesty, Sans could probably just be upset at how good Frisk is at getting away with shit like that, i mean if SANS tried it, he'd look like a freak, but when FRISK tries it, everyone is surprisingly okay, Frisk you no consequence asshole, good job~