Winter had sex with Sebastian plenty of times in the past, and she knew that he was packing down there.
Judging from the shape, it was obvious that Sebastian was half erect… for no reason at all. Because Winter was still wearing her black dress with an apron, he had no reason to get hard.
Besides, she doubted that Sebastian actually had any lust for her. He might've joked a few times and had sex with her when necessary. But he didn't go crazy over her body.
'If he were, he wouldn't reject me whenever I wear my lingerie to seduce him,' Winter thought.
His rejection was one of the reasons that Winter became so conscious about her body; Aiden had never rejected her advances.
In fact, Aiden would charge like a bull and carry her to the bed the moment he saw her with her lingerie.
Thus, the only plausible explanation for his half-erection was another woman.