"I can't believe a great beauty like me can't even afford to buy lunch. I think I've gone drinking too much this month. I would be ashamed to eat this (her bento consists of the following: plain rice and four loaves of bread (fish? tofu?)) in the office... A person like me, a vegetarian who is so beautiful as to drive men mad, has a responsibility to not show shame in front of people."
That is basically how Shikijou Saori sees herself. She is indeed beautiful and uber sexy. She uses her oozing sexuality to attract males, even if they're her students. Who she really wants, however, is Misato Suguru himself. She doesn't really explain why she favors him, but I suppose it's because when he meets Mahoro, he no longer acts like a hormone-driven teenager around her... most of the time. So yeah, I think she considers this a challenge.
Saori is a competitive woman. Because Mahoro unintentionally gets not only Suguru's attention but also most of his male classmates', Saori feels that she has to squash her competition. She flaunts her body, especially her ample bosom, when Suguru is around. She also has no qualms about wearing clothes bordering on indecent, pressing his face on her breasts, and glomping onto him/rubbing her body against his in public. Her (hentai-ish) daydreams involve her teaching Suguru the basics (or giving private lessons) in you-know-what ^^; She wouldn't hesitate to stalk, I mean, follow Suguru around, even when he and his friends are just going on a picnic, or if he and Mahoro are on a date. She'd wear a costume in a fifty-degree weather if she has to, just so she would be able to keep an eye on him. She thinks that if she leaves them alone, they'd do something totally perverted... and she would totally miss out on it!
Saori is not only competitive, but also proud and (sometimes) envious. She's miffed that Mahoro not only has a license to drive any vehicle, but also has a classy convertible. Although Saori only drives a yellow moped, she's a pretty fast driver. That's one of the things she's proud of... That and her humongous bosom. Crazy woman is what she is.
She may be beautiful, but she's quite a slob. Her apartment looks like a pig sty; dirty dishes pile up on the sink and counter, beer (sake?) bottles litter on the floor, and test papers are strewn all over her desk. She doesn't take a bath in her own home; what she does is use public facilities (for example, school pool and bath houses) and even Suguru's own bath tub. She also likes going to the Misato residence unannounced just when Mahoro is about to serve scrumptious meals.
Saori is an interesting character. While it's true that she has a dirty mind (imagine a grown woman having the hots on a fourteen-ish year old boy), she really isn't that bad. I mean, she's extremely loyal to Suguru. She's even partnered with Mahoro to chase away those who are bullying him. Not only that, her competitive streak eases up by the end. She's even started calling Mahoro "'neechan" or sister.