how can I make an NPC sleep like a vampire, but not have the visible vampirism attributes?

Thanks.

Pardon me, but how does a vampire sleep?

Laid on their back, with their arms crossed.

I suspect the sleeping slab is the key, not the vampirism of the sleeper. Animation for furniture use generally depend on the furniture marker, not the user. Check the slab and see what animations are associated with it. It's probably possible to associate those with another item of furniture by switching the marker used.

This is what I though as well. However, without Vampirism100 (perhaps other vampirism abilities trigger it but this is the one I've tested.) the NPC sleeps on the sleeping slab as it would in any other furniture, and with vampirism 100, the NPC sleeps on it's back, arms crossed.

Kewl Hadn't noticed that before. All special animations & their conditions can be found in Gameplay → Idle Animations. The vampiric sleep has a condition set to it (GetVampire == 1) and it won't play if the character isn't a vampire. Now this can be fixed easily by changing the conditions OR even better; making a duplicate one that doesn't require the character to be a vampire

Since I only want this for one NPC, would it be fitting to add an OR getisid to the conditions?

Don't trust us - try it!

Indeed - you learn from your failures.

EDIT: Not that I'm inclining in any way that you are going to fail

Got it working, turns out something similar is done for NPC "roderick." Thanks guys.