at the end of a meal in a restaurant to use the water/ice in your water glass to wash you your hands.
Yes. But only for Mayim Achronim.
Other ppl might not know what you doing…. I would stay away and use the sink.
Under the table, classic move – but got to look around.
That’s how one of my rebbeim did it at chasunas etc.
No need to use like 5 oz though 🙂