Well that's a knot in her stomach. If someone who's ever said that to Trace shows up they are getting kicked in shins until they bleed, and that's if Umi is unarmed at the time. Disgust probably shows on her face for a moment, but they're sitting down to eat, so they shouldn't dwell.

"Y-yeah, I... um. Hm. Move on to what?" The big topic of the day is sex, and Umi is no expert.