I need your input! (Patreon)

I'd love to do another attribute swap/theft sequence like the one I've just posted since I'm really pleased with how that came out, but I need to know... what should the characters look like?  what attributes are being swapped/stolen, (it can be more than just bodily traits) and what is their relationship to one another?  I'm looking for high contrast swaps here, since the more thats changing the more fun it is to draw!  Drop some suggestions!