You need to lower your expectations in case you are looking for a decent erotic massage in Yerevan. Many salons are usually run by older women, who are not necessarily interested in a quality sensual massage. Their reputation is rather nasty as well. People say that the majority of rub and tugs in Yerevan are brothels owned by the mafia. Freelancers like Anita (https://www.facebook.com/anita.srah) and studios like Evita Spa (https://www.facebook.com/massaje.salon/) advertise on Facebook, the Russian equivalent VKontakte or Odnoklassniki.
Egoist (http://egoistmassage.am/) at Movses Khorenatsi 90 is one of the more professional massage salons in Yerevan. An hour shouldn't cost you more than $100.