goodhomie = undo betraying Rin.
rosebud = increases affection with all girls by 100.
lagfix = Resets the call stack which an early version of the headpat system caused to pile up and cause lag. Doesn't mark save as a cheater.
funinthesun = resets the beach event and makes it trigger the next Sunday.
fingeryourniece = resets Ami's events 'No One Can See Us' and 'Important Things' and gives the message "You now have the opportunity to be a better uncle." Guessing there's gonna be consequences to these events in the future.
iwillalwaysloveyou = increase Ami's lust by 100.
bubblewrapprincess = increase Ayane's lust by 100.
likemotherlikedaughter = increase Makoto's lust by 100.
heartofgold = increase Chika's lust by 100.
atreefallsintheforest = increase Futaba's lust by 100.
supermom = increase Sara's lust by 100.
thouartsick = increase Haruka's lust by 100.
youonlyliveonce = increase Kirin's lust by 100.
seemeafterclass = count Chika's 'Detention' lust event as having triggered.
wheredoesthetimego = "100 Days pass while you sit at the computer. It's almost like real life now, isn't it?"
That last line is straight out of the game. I thought it was funny enough to just copy/paste.