I think to some extent it's hinted at, with how, if Ivy had fucked Lena before, Lena needs to spend a will point to resist her shower advances. Ivy is pretty clearly seducing Lena and being dominant in their relationship, so it's not that much of a surprise that the whole arrangement turns into some sort of Ivy building her own lesbian harem here and "stealing" Holly from Lena. But it definitely isn't direct, like you say, and can be rather abrupt.It's not always do directly telegraphed however. If you play things out in such a way that Holly/Ivy gets starting by Ivy initiating the threesome with Lena in the shower, there is nothing to really suggest this should lead to Ivy taking over mentorship of Holly's sexual life.