"Badge-ing" is an exhibitionist trend in certain trendy nightclubs (Most commonly in California) It involves a woman taking a male patron (Almost always a stranger) into a more secluded part of the club (i.e. bathroom, service area, etc.) and giving him an orgasm (usually by means of a hand or blow job) then allowing the cum to hit her face and top portion of her shirt, then returning to the rest of the club without in anyway making an attempt to clean herself up, wearing the proof of what she just did as a "Badge"
"Did you guys see Chrissy tonight? She's totally badge-ing, she's such a slut!!"