He never has. He's aware of the lust he inspires in others but has never found anyone who inspires the same feelings in him. Lust is a weakness to be twisted and taken advantage of to bring another to his knees. Fei has no qualms about that. No morals to hold him back. All those had been torn from him years ago. Left him with a cold hole in his chest where they should have been, where they might have been once.
But he feels them, that numb inside of him tingling with sensation when he wakes panting from a nightmare, body shaking with fear and trembling with weakness. He'll moan at the feel of his erection trapped between silk pants and pressed into his mattress, making him rock his hips. It makes him moan. That sensation, the rush of blood in his ears, the almost frantic beating of his heart. And he'll give up on his pride and reach out with his own hand, stroking the same way/ he/ taught him, choking on his whimpers and ignoring the tears that slide down his face.
And for a few moments, he remembers what it must have felt like to be alive.
But in the morning, it's all gone and he's left as cold as the mess flaking on his stomach.