A sexual position utilized by swingers, especially swinger geometry teachers, carpenters (Jesus), and many others. A fucktangle is any shape made when several people link themselves together through sexual actions that closely resemble said shapes, shapes that include "tangle" in their names, i.e. rectangle, triangle, and rhombus...tangle.
"I need help with my geometry so me, my best friend's mom, and his sister totally made a fucktangle last night. Then we calculated."
"I'm so old, I remember when mainstream Republicans were basically decent people with differing views on economics and not a festering fucktangle of racists, Nazis and child molesters"