You can also use the Boobswell pads from New Texas. They have no effects other than direct chest growth, they last a few days, and they can trigger multiple times each.
Okay not sure when that tidbit was added or if it was just something I missed from the AS3 version... I got out of the habit of using the wiki with how often it was outta sync with updates.
To date, I still curse whoever added the restrictions, especially the Tittyblossom/Estrobloom one. It was meant to be an unisex item that gave you max rows with a chance of not working at all as a minus.