After Locutus became Picard again, he went to Risa to recuperate. There he was annoyed when several women expressed an undue interest in him. That was because of the artifact Riker had him put on his table - he didn't tell Picard that the African-looking statue was to tell women that the displayer wished a sexual encounter with a woman.
That's how he met Vash.
If I erred in the above, it's because (1) I didn't want to break off in the middle of a thought and look up the descript. (2) I can not get BBCA on my Verizon account. I tried, but got mocked by the Verizon computer system.