Is there a way to make cum stick to his body, like it does to her body?
Yes, it's possible. There's a popularity problem here:
only a subset of SDT players will attach a penis to the HER character
only a subset of the futa enthusiasts will also use the futa ejaculation mod
only a subset of futa ejaculation enthusiasts also want to see semen on the HIM character
Wthout a significant "fanbase" for an idea, it's difficult to justify the modding time involved in fulfiling it.
Related, could the floor level be changeable, or even have different levels across the screen? Scenes with furniture often end up with cum going through said furniture.
The "floor" doesn't really exist; it's just a set of hardcoded numbers.
animtools can make the characters stand (or kneel) at different points on the y-axis, because it doesn't really care about the hardcoding.
Extended hair physics can "add" a floor level for hair strands to rest against, but it
also doesn't care about the hardcoding; it just allows modders to define a custom y-value (which will probably be
similar to the hardcoded floor number, but doesn't need to be - you
could make hair strands float around a character's shoulders if you imagine that she's swimming).
The main problem is that the SDT camera/zoom system allows for
parallax between foreground element (character sprites) and the background image. Look at the preview image for
this mod. It's zoomed out abnormally far, so it's easy to see that the "floor level" defined by the character positions is totally inconsistent with the "floor level" suggested by the background.
Even if we
were to fine-tune the game's code to allow custom (x,y) coordinates for collision, such fine-tuning would be effective only if the player agreed to
never touch the zoom slider or hotkeys. If you're willing to
switch from "furniture" in background images to on-stage animtools props then this objection would vanish. It would be fairly easy to make semen strands adhere to animtools props.
There's a secondary concern involving
mod inter-compatibility. SDT's strand-handling code is poorly structured. It relies heavily on internal loops instead of hierarchical function calls or recursion. If you wanted to fix or extend the relevant line of code (
SDT.swf::obj.Strand.collide_l::681)
if(g.sceneLayer.globalToLocal(_loc2_).y > 1220 + Math.random() * 65)
then your mod might prove to be incompatible with the
moreCumSpurts or
sharpshooter mods, because they both deal with the same set of functions.
Note: this doesn't make the idea implausible or "bad". It's just that I probably wouldn't write the mod, because I'd feel very foolish if I released a mod which broke a bunch of my other mods.