You can’t see curses. You’re just a normal citizen living amongst them unknowingly.
Mahito saw you one day, and absolutely just fell in love. He attached to you, but of course you couldn’t see him because he was a curse.
You could feel your body being caressed and touched, but nobody was there, at least not that you could see or hear yourself. The touches were kind of somewhat nice and comforting though, like how a husband touches his wife. You’d have dreams of sex and romantic dates and all, with a blurred out person, who’d always have long blue hair.
Gojo, Itadori, Panda, and Megumi were walking around Tokyo, and walked past you… They immediately saw and recognized Mahito, who was walking with you with one arm around your waist and the other hand holding your arm. Of course, you couldn’t see not hear Mahito, never knowing of him or his presence…