Aw sure. I like there to be a maximum contrast between human & monster anatomy... foreign bodies to one another, different in every way. The sort of thing to create maximum dissonance and dysmorphia in a cross-species adoption case.

It's canon in Undertale at least, that monsters don't 'digest' food in the manner humans do... 'monster' food is entirely absorbed into their bodies, they do not turn it into mush and expel it as humans do. Though, it is implied they could willfully ? experiment with this ? via consuming Human Food ?! So. There must be Something down there, though it may not be as defined or complicated as human anatomy.

For deltarune... it can only be said that as Kris is repeatedly flushing the toilet, Toriel awkwardly explains "uhm, Kris does this sometimes..." ... is there even a 'bathroom' at school ... ? Is it necessary there be one...? Do monsters in a monsters-only community typically have such a thing...? Not all buildings may have this.... though the Holiday house does, but it is a mansion owned by the mayor, and could be an accommodation she made... [shrugs] a lot is up in the air.

I would like Human Bodies to be... bizarre, perhaps grotesque or macabre things, filled with blood, throbbing and pulsing and dripping and leaking and shooting out fluids from every orifice... biology as it is, put in a context to feel absurd. As Kris ages, I would like this to feel excruciating, like they are stinking and sliming all over. This body, that refuses to let itself be ignored, be unknown. Oh the demanding quality of a boner, accusatory in its action. I WANT I WANT I WANT!!! It's like a built-in gun that cocks at its own will. PLEASE do not threaten my life, my friend's lives. PLEASE I DON'T WANT TO SHOOT ANYONE EVER!!!

.... for my own purposes, I have no need to imagine monsters with a binary sexual physiology ? If no blood flowing through veins, why have a boner? Why penetrative sex? I don't believe there would be SPERM and SEMEN and EGG and OVARY ... not so physical!! I have. NO need for Asgore, Berdly, or Asriel to have a cock. I DON'T!!! Jockington.... Rudy......... it is in fact Funny to me if Toriel and Asgore are not very different when undressed. In reality the two have different numbers of fingers, even... it's interesting to think there could be this near-infinite bounty of silhouette contrast (a watercooler is as much a monster as a bunnygirl), but little distinguishing them beneath the surface. Just a dry flow of magic & dust... the external aesthetic does not define so much.

Berdly is out there daydreaming about so much as having nipplies.... is this because he is a 'bird', or is this because he is a monster ??? Spamton mentions... a mamel's milk... we have only the most obtuse ssstupiddddd data about this... obviously monsters can have Boobs.... we see Boobs. and I like boobs. So there can be boobs. Not 100% of the population, though.... Woshua doesn't have nipples.... probably....

So for Asriel/Ralsei and Noelle, I like to envision a very similar 'slit' between there legs... an exit that human food may pass through if ingested, but not actually a urethra/anus (and materials are not being composted/fermented in gut). Not seeing daily use like human anatomy, which is always churning perpetually to stay alive (and thus, more hardy, more holding them together, but short lived). An indistinguishable little slit... Asriel and Noelle's both pink-hued, obscured by white fur.... interesting to think of how different body types could result in more differences in shape than something like 'gender' ? There could be Some motivating factor towards same-species couples being the Norm, maybe an ease of producing offspring, but in the sense that even if you and your refrigerator boyfriend both had compatible bodies in one sense, it could be an ordeal to actually align your bodies safely.... [shrugs] or maybe something about the silhouettes has to be close enough, who knows....!

Novel to me to imagine monster breeding being a matter of pressing, crushing, kissing slits together, lying on one another, pressure and contact which initiates a transfer of magic ? more ritualistic or symbolic in some way... not stabbing penetration and blasting hot fluid into, like humans do.

When I imagine Kris penetrating Asriel or Noelle... [closes eyes] I imagine it feels like... being stabbed, firstly... an intrusion into the body, and, as if it will reach completely inside, into their chest, which is not protected by muscle, bone... there is no 'container' to hold the cock like a human vagina, no sleeve mere inches deep... the body could be bent and crushed so as to reach deeper, deeper... shooting inside could feel like, it's filling the body cavity itself.... stab, stab, stab, stab, it's excessive, pounding, violent, one has to be a masochist to want this, and luckily, BOTH of these individuals ARE. Their bodies are not built to endure this, which makes it feel more perverse for Kris to intrude this upon them. It will feel selfish to want this. And crude...

I also like to think a lot about hotdogging through, shallowly rubbing, mild pressure, a lot of this kind of, grinding... easier ! still embarrassing for Kris, but closer to something a monster body accommodates...!

Uhmmm. My other thing is that, human bodies attempt to incorporate whatever is put inside of them, absorb things, but monster bodies do not have this, and human materials contrast their own dust bodies. So I think if you came, or pissed, inside of the slit, it would inevitably seep back out, it would not be soaked inside, no matter HOW deeply you shot.... uhhh intoxicating for me to think about.... we can't begin to think about pissing down oniichan's throat... it's ruinous stuff.....

But Kris. I do like cockkkkk anatomy, it just feels appropriately humiliating to me~~ but I also love to imagine gynecomastia onset at puberty... it's not uncommon in many populations of humans... small boobs, not hefty but, buds.... it'd be nice to have something to feel more neutral and [shrug] about.... ! Not erm, a 'problem' like the cock is, they don't be leaking... it's fine. Not a problem. Oniichan could find it soo cute. Noelle I think would be like.... THE WHAT ? BOOBS ? WHEN DID KRIS GET THOSE ?!?!? ... [struggles]

as for Noelle and Azzy, the door is open to imagine some sort of chest so why not....! small breasts on Noelle... I imagine Azzy flat by nature, and nipples are generally not obvious unless one is brushing aside fur to find them. I wonder if interaction could encourage growth or something.... I wouldn't say I Need it, I enjoy oniichan flat chest of the group, but also not opposed to little budding Azzy.