Erotic massage salons in Marbella are in an ambiguous twilight zone. It’s a resort so naturally there are some superb masseuses and studios but there are also whole villas being rented out and transformed into luxury bordellos, where the massage is usually only foreplay.
Nikky’s Mass (http://nikkymass.es/) at Avenida de Manolete 11-12 has great looking girls and unusual options like a “mutual massage” with a happy ending, described as “giving the pleasure back, sharing it” with your massage therapist. Happy RelaxTime (https://www.happyrelaxtime.es/) at Camino del Ángel, Puerto Banús local 34 is also a great massage studio with stellar reviews and everything you’ll ever need to release all that stress you’ve accumulated while sunbathing on your yacht.
Villa Romana Marbella (https://www.hotelmarbellaromano.es/) on the city’s outskirts at Calle Victor O'hayon Taplero is one of those converted mansions I mentioned earlier. They promote themselves as a club for adults with a huge section dedicated to massage. But they have also rooms where their guests can stay and organize various events and parties. I will leave it to your imagination what can happen there apart from an erotic massage (masaje erotico in Spanish). Prices at massage salons in Marbella start at about €100 for the basic stuff but most likely you will be strongly encouraged to opt for more expensive packages.