Triangle Hair

I have thick, shoulder length relaxed hair that grows outward instead of down. As a result, my hair usually resembles a triangle or pyramid like Rosann Rosannadana. I read somewhere that thinning out the hair or cutting the "bulk" from underneath helps the hair fall down instead of out, but my stylist is dead set against doing either option. Are there any methods I can try to lessen the triangle look?Thanks,Renita