Since no one answered your question about the act itself (thank you, scoed, for the great info though, always smart to know so you can be prepared), I thought I'd chime in here
As a bottom, and with my personal Top, I have been showered and I have drunk from his golden fountain

but we are fluid bonded and have been for many years. In a session, I will only allow on me, and I definitely find it a turn on, but not necessarily humiliating.
As a Top, I have yet to have a session where someone wanted to drink from my fountain

Clean up duty, yes, but most prefer it ON them, and I love to piss on a guy's cock while he is masturbating furiously....such a marking of the territory feeling, so to speak
K
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Switchy, and only sometimes bitchy ;)