Make them even bigger

Of course he should continue. One of the nice things about bigger tits is there is more breast flesh to cover with the growth potion. Duromast grabs Cinnamon by her short black hair and pulls her back even further, forcing her breasts high into the air. The firm orbs rest proudly on her top of her chest almost defying gravity. She's been obediently keeping her hands clasped behind her head the entire time, but wrenching her further backwards causes her to slip momentarily, but she quickly corrects herself.

The demon once again takes the red flask of breast growth ointment off of the table and pours it over her upturned tits, completely covering them in the thick sticky fluid. Then, like before, he begins to roughly rub the oil into her breasts. Her tits are big enough now that he can't completely flatten them with the palm of his hand, but he squeezes, shakes, smashes, and crushes them as much as he can without thoroughly bruising them. As the ointment is starting to be absorbed he again goes back to slapping her tits, smacking the one into the other, beating her throbbing melons in an almost idol manner as they continue to grow.

Finally he releases her, letting her stand straight once again. He tells her she can lower her arms, and immediately she cradles her sore throbbing tits, looking at them with bewilderment. Her tits have grown to the size of two large watermelons. Each of her now visibly veined breasts weights at least fifteen pounds, looking ridiculously massive against her slender eighty pound body. They're too large to maintain that perfect firmness, and now hang low on her chest, almost down to her navel. Her nipples too have grown in size, the black bumpy and crinkled flesh of her areola widening to about the size of one of her splayed hands, and capped with huge marshmallow sized nipples.