The act of lowering yourself onto your knees over a lit candle so the flame is essentially roasting your nuts while you beg for mercy as you kiss your sexy gals ass and/or eat her pussy out from behind and she slowly pushes down on your hard cock to bring your nuts closer to the flame until they either catch fire or she orgasms, whichever comes first...and if they end up on fire you'd better do a real good job of kissing her ass til she comes if you don't want them burnt off. A very sexy way to show you are hot for her.
I let her give me roasted walnuts last night and ended up with black balls before she came...but the kisses she gave them to make it better was worth it. (and yes, she did end up setting them on fire, but only because her orgasm in my face was so intense that she ended up tightly grabbing my cock and pushing down on it...making me end up comming sperm that was smouldering as I happily suffered for being that hot for her! Ouch, can I have some more please?)!