Pulling a crass is where you stay behind unknowingly at a major sporting event while your ride and supervisors leave thus having to return for you and you look like an ass or crass
Stupid crass, two years in a row pulled a crass at state wrestling, that stupid jackass
lacking refinement, good judgment, intelligence, and sensitivity; very stupid and lacking sympathy or understanding in any sense
A crass remark had been made about my grandmother not having good comprehension and being slow to process information she receives because of her old age.