How do you deal with mana on Primal Beast?

The Torte guide and the Immortal Faith one absolutely do not address the fact that he has the mana to cast his spells once. Immortal tells you to get soul ring, which doesn't actually help with doing the 4 buttons because it's still 120 mana per idiot stomped with 0 regen afterwards.. Torte tells you to get bottle which only works during the laning stage and then never again.