It reminds me that I once went to a salon for a haircut (yeah, I know how that makes me sound) and the woman washing my hair gave me a head message (part and parcel of the haircut I'm sure) but she started making groaning noises, which felt surplus to the standard offering. She also brushed her tits on my head frequently during the actual haircut.
This actually created something of a dilemma when it came to the tip. I did not know the etiquette if any of it WAS an addon. I didn't feel too guilty to pay a standard tip though because she hadn't asked for consent.