Hello Trev. Yes, it's a wager cup.
The skirt of the woman forms the large cup.
A second cup swings on pivots above the woman.
In order to win the wager you had to drink both cups dry before setting the vessel down.
In a previous What-is-it question we presented a different style of wager cup, a Mill beaker. Check here:
viewtopic.php?t=7325Pat.
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