That's because Tod
is a girl. You see, she was masquerading as a boy. Asokil had the 'advantage' of being pressed up against her, you see... need I go into further detail?

. Long and short of it was, he saw through her disguise - a very good disguise, mind you, but uh, certain traits, namely one's build tends to be a slight giveaway - at least, when pressed against someone.