No Nut November - Day 17

What simile would you use to describe this bust? I feel we're past watermelon stage and not quite at beanbag stage...

"Her breasts flowed downwards, their massive bulk resting on her warm lap. The dress's straps held on for dear life trying to cover the monstrous orbs - the slightest tug threatening to rip away all pretenses of modesty."

Eh, that's the best I can do, and I didn't even compare them to bowling balls!

Give us your literary techniques for describing egregious breast sizes in the comments!