That's because you haven't figured out yet that it's really intended to sell a game... a DRINKING game!
I've got a few of them figured out already.
One drink when:
Rina drools over a guy extra drink: Rina drools over Balmung
Mirelle drools over a rare item (or says 'rare item'
Shuugo drools over a doggie
Shuugo drools over a girl extra drink: Shuugo drools over Rina two extra drinks: Rina drools over Shuugo
An unbeatable monster appears
A high-level character attacks the unbeatable monster, and it instantly heals
Shuugo uses Data Drain extra drink: Shuugo uses Data Drain in public
Shuugo gains a level
Shuugo loses a level
Shuugo loses a tooth