And to answer my question:
Torah is compared to three liquids wine, water and oil. Compared to wine in the sense that the more your drink the more thirsty you become – מגריר גריר. A person who learns a drop of Torah may feel satiated, but when he really puts himself to it, he feels the urge to go on and on. מגריר גריר. That’s why you’re “allowed” to learn erev Shavuos! Just like drinking wine Erev Pesach, a lot is allowed, a bit not.