Overgrowth

By the time she had made it to the other side of the room, already lowering Simon into her top, she felt a sudden surge of something blast it's way through her body like a freight train. By the time it had made it's stop and unloaded it's cargo, she had dropped Simon, fallen back onto her bed and broke it in half, knocked over almost all the furniture present in the room, and torn one of her plus-sized bras asunder.

Her jeans managed to hold a bit longer, but she could feel her bare flesh making contact with the ruined remains of her bed. There was certainly a lot of Lilith present in the room. She paused, blinking rapidly and shrugging off the pleasant sensations, and then looked down between her open legs and found Simon, looking tinier than ever.

Simon, flat on his back, gazing upward at the enormous girl before him, was at a lost for words. He sat up, observing the landscape of their dorm room. Except he couldn't take much in. Aside from his side of the room, which had managed to survive Lilith's second spurt, all he could see was Lilith's shapely legs and meteoric breasts which wobbled overhead ominously. Her sweater had survived, but her breasts had swollen to a size far too large for anything in her wardrobe to manage. Maybe that quilt she kept under her bed for cold days would be more fitting.

Simon sighed with a mix of relief and frustration, then noticing a small bottle pinned under Lilith's thigh. "Hold still." He said, rushing in and gripping the top of the bottle. Lilith, taking notice, attempted to lift her massive left to assist him but ended up cracking a shelve against a wall. She then settled into a state of stillness.

Martin Fink's Ecstatic Ethereal Enormifying Elixir. 

Simon stared at the label, and then skyward up at Lilith. "How much of this did you drink."

Lilith blushed and giggled, her mammoth breasts wobbling. "All of it."