Tattoo artist Jamie Clinton gives 22-year-old Danielle Rondeau a tattoo of a blue bird on her ribcage at Stingray Body Art in Allston. Danielle Rondeau, 22, a senior sociology major at Northeastern University, calmly lies on her side on top of a black, padded table. She sighs quietly, her body relaxed. “Ready?” asks her aunt Marie. Rondeau lifts up her black V-neck T-shirt, revealing her midriff and a small metal post through her bellybutton. Rondeau remains still and collected, seemingly unaffected by the constant sound of needles buzzing in the narrow cubicles surrounding her. “Good to go,” she says. The...