ROFL!!!! I was looking at the link Hannah L. gave, when my little brother walked in on me. "Cool! Bullet proof vests? Can I have one?"
Hahahah! That was awesome.

I'm thinking breasts won't be an issue with kongs et al because by the time your legs are through in the tuck you should be starting to bring yourself upright; but I could be wrong. My guess is that if you are okay with being in a tucked/squat position (or something like child's pose in yoga), a kong should be fine.
I have a teeny chest, but once a month I get what I call "real woman boobs," and the past few years they have gotten so uncomfortable I usually end up wearing a sports bra day and night during that time. Even then it hurts to walk.

Any suggestions for how to mitigate this (besides reducing salt intake)?
Just dealing with this for a few days a month is crappy enough. I don't know how you ladies with "real woman breasts" handle it 24/7... and practice parkour to boot!