Issues i encountered:
if you interact with the cylinder and choose the jewelry it says "gift it to someone" after it Genny (forgot the name sorry) says "thats for me? thank you" and her friendship goes up 1. jewelry also didnt consume so you can actually "spam" it to level her
If you have a sex scene with Lin and do another one after it sometimes it flashes a picture from the sex scene before between the animation change
also, its nice if you say "thats all for this scene for now" but thats a half lie because if you get the friendship higher the scene has some extra scene like the tongue kiss while dishes or the second squirt while cooking or the breast suck in the bath. so i actually never know if thats really "it" or if scenes have another change on X