Chrissy Teigen has fired back after being “roasted” on social media for her “dirty” bathwater. The 38-year-old model has defended her bathing habits following backlash from some fans online over a video her husband John Legend shared of her in the tub. Posting the same clip on her own Instagram account, she wrote: “Currently getting roasted online for being dirty because no one listened the the audio where I say I’m soaking off body makeup (to shower after!) “Full blown fights in John’s comments. My favorite is ‘baths are not for bathing.’ “I love a good old fashioned roasting though, u guys a…