From my perspective, I find it totally erotic, pulse quickening and irresistible. As several people have mentioned elsewhere, there is a cost to be paid though. Frankly, it doesn't take a rocket scientist to realize that the Bull's confidence goes straight up (which is an additional turn-on for the woman) while the cuck's self-image is ... well, shall we understate it and say "tarnished" a bit? Every time the cuck participates a bit more of his masculinity is stripped away.
For the Bull and his slut it's a fantastically arousing game which leaves them both feeling deeply satisfied. For the cuck it's like a ******* addiction which promises ******* in the short run but delivers emasculation and sexual dysfunction. When you think on it, it's simply nature taking it's course.
Bulls plant their seed in many willing partners while the cuck is marginalized and removed from the sex game.