Teens masturbate. Just do it in privacy and don't make a big deal out of it.
It IS quite Normal, certainly at your age. How you 'Dress', or not, yourself is a Personal Choice. As regards your Parent's reaction, well you know 'Mum & Dad' best. Personally, whilst I would 'Understand' perfectly, I might encourage my Son, or Daughter, to perhaps do this Privately- in their own Bedrooms.... rather than In Front of Great Aunt Lavinia!