Omega Geralt sees Yennefer again and introduces her to Alpha Jaskier. Jaskier doesn't know her and sees her as a threat. He puffs himself up and clings to Geralt while growling at Yennefer. She's not scared in the slightest, she's actually fighting to not laugh. Meanwhile, Geralt is just facepalming.
Oh there is no doubt in my mind that Yennefer would take great pleasure in ruffling Jaskier's feathers the moment she realizes that the wispy bard (in comparison to Geralt) is not only an Alpha, but he's the WITCHER'S overprotective Alpha! As if Geralt needed protecting! She knows it bothers Jaskier just as much as it flusters Geralt (who does not know to deal with his protective Alpha at all and is generally just bewildered, because Witchers are not precisely your standard idea of omegas, he was not trained for this, how make bard calm the fuck down???).
Cue Yennefer giving them grief at any and every opportunity just to see Jaskier flash his teeth and preen like a peacock. And if that means Geralt begins to appear with more and more evidence of their bond -- braided hair, the constant scent of his Alpha, hickies and trinkets and generally just looking well rested beneath all that embarrassment -- well then good. Three birds with one stone.
She gets quality entertainment. Geralt gets taken care of. Jaskier gets to do those Alpha things he can't particularly do when it comes to protecting Geralt from his job and monsters.
Win, win, win; even if those dumb, dumb boys are too distracted and too stupid to see it that way.