You're so cruel to him XD
Lust could be overpowered by Nicholas even if she put up a fight but it just wouldn't be anywhere near this easy. But it was all part of the fun. She let out a strangled scream but quietly smiled when she felt him enter her and wanted to laugh at his cry of relief. Silly boy.. the best part about it was that sex with Lust was amazing every time. Faux violation or not and no matter how much he might hate himself for it later, he'd always remember that he enjoyed it.
Lust stayed pressed close to Nicholas as he did the deed, sniffling in his ear, small sobs that would break mortal's hearts coming from her. Perfect replicas of one's she'd heard before so knew were effective. She may be a Sin but she never felt bad about what she did.. just like with Nicholas. He could pretend to be the nice guy all he liked but he really wasn't. If this beast wasn't in him all along then there was no way this would have happened. Lust did not create, she simply unleashed what was already there.