No more boob soup for you.
Deodorant seems to be a "magical" way to combat boob sweat.
"Deodorant is magical. I use it for my lack of thigh gap with dresses, underboob sweat, and of course, its intended purpose. It also works to keep bug bites from itching, but ONLY if you haven't broken the skin." —tiffaniambert
If that hasn't worked for you, try your luck with gel deodorant + anti-chaffing gel.
Secret Clear Gel Deodorant down the middle and across the bottom of my boobileens, then Monistat Anti-Chafing Gel in the same areas. That anti-chafing gel is a lifesaver for big thighs and not too bad as a mattifying primer either.
Fox Searchlight Pictures
Stuffing your bra with tissue paper is nothing to be ashamed of anymore.
"Kleenex stuffed in bra, usually folded between." —sk8rtoon