This was what I originally had planned for the previous comic before realizing I really needed to address "why not just buy more potions" question.
Susan is talking to someone who looks like a bunny girl version of herself to answer the question "are the potions previously used on NPCs still in effect". Granted, that form's the result of an asset-swap potion, suggesting there simply are bunny girls who resemble Susan in this world, but I'm banking on people not assuming that.
I normally wouldn't have someone suggest making such noises in this comic, but blame the Fable games. What bunny-Susan is suggesting are emotes you can do in the games to impact NPC opinions of you (for good or bad. Different characters would want to see different things).
In Fable 2, there was an area of effect to this. You could start whistling in the middle of the town square, and anyone nearby would react to it. If an NPC was a merchant, this could affect their prices, and how much their shops would cost to purchase. You could also farm reputation this way, which was useful, as some missions had minimum popularity requirements. As another bonus, NPCs might have gifts depending on what they thought of you.
Point being, it was fairly easy to do, and there was incentive to do it.
In Fable 3, emoting was targeted, by which I mean there was a sort of emote mini-game that only affected one NPC at a time. I felt that change was for the worse, and I generally didn't try to impress NPCs in Fable 3 without some very specific goal, such as it being necessary for a quest, in mind.