auntcest

noun

auntcest

noun

Etymology From aunt + -cest.

1

Rare, Slang, Vulgar Sexual relations with one's aunt.

http://www.news.com.au/entertainment/tv/game-of-thrones/gots-tyrion-fan-theory-is-wrong-hes-not-a-traitor-or-jealous-of-jon/news-story/431692da22d582b59f61ba0ddee19eb0
http://www.digitalspy.com/tv/game-of-thrones/feature/a835352/game-of-thrones-children-of-the-forest/

1 more example

Daily Telegraph Well, he’s a wee bit late with that, because Jon and Dany don’t just lock lips, they lock a lot of other things too, in a steamy spot of what can only be called Aunt-cest.

Entry derived from the Wiktionary, under licence CC BY-SA 4.0 — list of authors.