It’s Indonesia. Without a doubt any massage in Denpasar, erotic or not, will be amazing. I mean: Bali is literally on every massage stock photo. Balinese massage can be a lovely experience, even when it doesn’t “end happily”. It’s more of a spiritual thing.
Jalan Legian, the main street in Kuta is where you’ll find the best deals for foreigners. You can buy an hour of steaming hot massage for $10. Tip another tenner and you’ll get yourself a happy ending. Karma Massage (https://karmamassagebali.com/) and King of Pleasure (https://pleasurebalimassage.com/) are examples of sensual massage studios doing only outcalls.
There are also rubs and tugs in Denpasar, but they are not always foreigner-friendly and mostly operate on a “by locals for locals” basis. Safe bets in Denpasar are the Sriya Spa (https://www.facebook.com/SRIYA-SPA-BALI-917912551599535/) at Jalan Mertasari No.90 and Refrezz (https://refrezzspabali.com/) at Jl. Tukad Batanghari VI B No.6.
Soapy massage salons (also called Soaplands in Japan) are a typical Asian phenomenon and offer many extra services in addition to massage
Keep also an eye out on soapy massage parlours. They’re supercharged studios that usually have full service on offer. Packages cost $50 at the most and that includes a hand job. The rest is to be negotiated separately. And last but not least: there is the rather famous Riverview (https://www.riverviewspabali.com/) at Jalan Kresna No.04 in Kuta.