I did it boys
Alright folks I'm gonna spill the beans
For Ami sucking scene you'll need to get all possible lewd points before the teacher's room part, i think is 5 in total. For her to sit on you just get 1 or 2 lewd points, but it cannot be zero, or you lose both options
As for the infamous kissing scene you will need to play a full love route without collecting a single lewd point or choice, than when you reach the part with a timer you pick the second option. If you pick the first option you get another scene, but letting the timer run out you lose both.