Cuckcake
A cuckcake is the outside female partner in a cuckolding or cuckquean dynamic: a woman who has sex with one member of the couple with everyone's knowledge and consent. Unlike the bull, who typically occupies a dominant position in the dynamic, the cuckcake role carries a softer connotation. She is desired, sought out, and welcomed into the dynamic rather than positioned as a figure of authority or threat. Her presence is the thing the couple uses as erotic material, but the power architecture around her is different.
HISTORY
"Cuckcake" is a very recent coinage with no traceable historical lineage. It appears to have emerged from online kink communities in roughly the 2010s, combining "cuck" with "cupcake". The earliest Urban Dictionary entry would likely pin it down more precisely, but it has no equivalent to cuckquean's 500-year paper trail.
It's interesting to note that unlike the gender equivalent term "bull", the term "cuckcake" has a softer feel and doesn't denote the same power structure and dominance over the cucked person.
Catherine de Medici spent nearly 25 years in one of history's most documented triangles. Her husband Henri II was devotedly, publicly, obsessively in love with Diane de Poitiers, a woman 20 years his senior who had been his companion since his adolescence. Diane ran the court. She chose Catherine's ladies-in-waiting, managed access to the king, and wore Henri's colours at tournaments while Catherine watched from the stands. Henri's initials, interlaced with Catherine's, formed a shape that looked like a D. Catherine noticed. She had a hole bored in the ceiling above Diane's chambers and watched them together through it. She commissioned portraits of herself in the nude, modelled on Diane's likeness, as if trying on her rival's desirability. She endured it, stayed, produced ten children with a man who publicly preferred someone else, and said almost nothing for 25 years. When Henri died, she moved with absolute speed: stripped Diane of the crown jewels, reclaimed the Chateau de Chenonceau, and spent her widowhood building one of the most formidable political legacies in French history.
None of this proves an erotic charge. But the hole in the ceiling is hard to explain any other way. Catherine was not a woman who lacked options or nerve. She watched, she stayed, and she waited. Whether that watching was purely painful or something more complicated, only she knew.