A man bidding tons of cash for a teenage girl's virginity is creepy enough, but in case you think that's okay, Dr. Crab cranks up the creep factor to eleven by how he behaves afterward.
After taking Sayuri's virginity, which causes her to bleed, Dr. Crab saves a small amount of her blood in a little vial. Ick. And, to make it even worse, he doesn't even spell her name right on the vial. If you're going to be a gross weirdo, at least be a gross weirdo who can spell.
Arthur Golden makes Dr. Crab so creepy-crawly to make sure we are grossed out, because to Sayuri, this event isn't all that strange. It's just another day in the life of a geisha.