When a rogue kisses you, count your teeth.

[Ven a ganef kusht, darf men zikh di tseyn ibertseyln.]

[װען אַ גנבֿ קושט, דאַרף מען זיך די צײן איבערצײלן.]

(Other Authors and Sources)

Yiddish proverb
    (Source)

Alt. trans.: "When a thief kisses you, count your teeth."