I'd give you a little sample of what I'd think it could sound like but I don't quite have Jaskier's lovely voice. I could help give him some ideas, though I'm sure he's chalk full of them already. 

[ Is this her teasing Geralt? Maybe. Just a little bit. It's mostly just to test the waters and see what that would feel and look like because quite frankly, she hadn't before. As soon as he's over she relinquishes her hold on the log just as it falls back into the bog. Dusting off her gloves, she falls back into step with him. The jungle around them seems to follow them, watching, waiting. Vines twist out in front of them making the path ahead uneven and bumpy.

To hear that his brothers had dwindled from thirty to...what she has to imagine is far less if the noise preceding it is any indication. It gives her pause, eyes flitting towards Geralt immediately. ] 

Four brothers? I can't even begin to imagine having four. Although Holst is sometimes like having four wrapped into one incredibly large body. [ She grins up at him teasingly. ] Who was the troublemaker? I bet it was you. 

[ So engrossed in her teasing she doesn't sense the way a vine creeps towards her with the intent it seems to snatch her up by her ankles. ]