If your a dancer your supposed to shave everywhere right?

i dance and i saw a show and they had to just wear dancing shorts and shirt and they ddnt wear udnerwear, your not supposed to right? and do u shave everywhere wen you perform and practice? how do they keep it from not growng back??? and not showing like on stage? they ddnt ave ay tights eathier. oh and how are u supposed to not wear underwear wen u dance if u have your period? or othe things?