Pricing for Massage Places

[nostromo]

it has no meaning for appreciation of the service rendered as in other industry.

if you just tip without asking for anything, then you have the right to call it tips.

You're contradicting yourself. It either does or it does not have meaning.

In RnT, tipping is commonly used to describe both the act of exchanging money for the services received and the act of giving money above the agreed amount in appreciation of the services received.