nah 100% eric was giving them something
For ann you see her smoking on the balcony eric before the nightly lessons, thats why shes so nympho and horny
For alice route you see hints of it first when you first got to his apartment and his secretary asks if he wants the usual delivered, then you later see it in action (a few scenes later) where alice refuses to have sex with eric but then goes to smoke, then you see the fucking on the couch and alice has lost all inhibition, the next day when you confront her she says she doesn't remember what she did
i was curious if we ever found out what exactly it was