It basically means women are allowed to commit statutory rape, but only if the victim is a virgin. And after that she owns him. They mention that the reverse is in place for female virgins, but they get to demand whatever man they want for their first partner. There isn't any detail about whether or not he can tell her where to head in or what sort of obligations are incurred by such an encounter.

More like morally repellent, and I'd think Nynaeve might have something to say if people started it up again.

Yeah, she could use the weave to attract fish, but until she saw the technique used to grab them, had no way of making practical use of it. Siuan is unlikely to have taught her, since she would have learned to fish on the ocean and a major river. I doubt there were any peaceful little tributaries running through the Maule from which someone could fish barehanded. Depending what kind of nascent industrial development existed in Tear, you might not want to eat any sort of fish in such a body of water, and anyway, in a major city like that, they'd have fished it bare with nets and such. Siuan might be good with a boat or a pole or a net, but she'd have no reason to bother with the barehanded stuff.