This is a spin off of my homestuck thread so the rules of those apply to this as well
But to those who don't know the rules
You can post sfw and nsfw headcanons

Also I'm going to post a headcanons I just thought of

Toriel is the throat goat (pub intended)

oooooo interesting thread! now lets get some yaoi in here. i think sans 100% gets boned by grillby after hours (pun intended)

Once Frisk grows up, they will 100% end up a monster fucker.

Mettaton EX has huge tits hidden in his chest, and they pop out when he's horny.

Mettaton and papyrus both are switches, and switch the dom-sub role often. Papyrus is not the innocent dumb fuck like everyone thought in 2015

I’ll never be convinced that Toriel somehow ISN’T into mommy kink

This is a really silly one.

After sex, Toriel would definitely indulge in a bit of post-coital pie. That woman loves pie too much for that not to be the case.

Hear me out... My headcanon is that Undertail = Undertale.

Mettaton has like 500+ different attachments for different fetishes and stuff hidden away, including attachments for making them female.

oh a 1000%! hes gotta be kinky!

Asriel absolutely used his god powers to look through the memories of Asgore and Toriel to see them naked, even if not for gratification, but out if curiosity.

hehe definitely, i think it would start off with curiosity then to gratification ;3

Toriel definitely into incest!